The West's Vanishing Snowpack: What the 2026 "Warm Drought" Means for Fire Season

Abstract

The winter of 2025-2026 has emerged as a paradigmatic case study in the rapid climatological transformation of the western United States. Characterized by a severe and widespread "snow drought," the water year has defied traditional hydrological expectations. Despite near-average precipitation in several key watersheds, the Western cordillera faces record-low snow water equivalent (SWE) metrics, a decoupling of moisture input and storage that threatens the region's water security. This report provides an exhaustive analysis of the meteorological drivers, microphysical snowpack processes, and hydrological consequences of the current water year. Synthesizing satellite telemetry, ground-based observations, and atmospheric reanalysis data as of early February 2026, we explore the transition from "dry snow drought" to "warm snow drought." We further examine the specific atmospheric architecture—including persistent ridging and a modified La Niña signal—that facilitated this event, alongside the micro-scale physics of sublimation and albedo feedback that accelerated snow loss. Finally, the report assesses the cascading impacts on reservoir operations, specifically within the Colorado River and California State Water Project systems, and the implications for the impending 2026 fire season.

1. Introduction: The Decoupling of Precipitation and Snowpack Storage

In the conventional hydrological model of the American West, winter functions as the season of accumulation. The great mountain ranges—the Sierra Nevada, the Cascades, and the Rockies—serve as vast, natural infrastructure, capturing moisture from Pacific storms and storing it within the crystalline lattice of the snowpack. This temporal delay, holding water in a solid state until the thermal pulse of spring, is the cornerstone of western water management, allowing agricultural and municipal demand to be met during the arid summer months.¹ However, the winter of 2025-2026 has sharply deviated from this historical norm, presenting a scenario that challenges the fundamental definitions of drought and resource availability.

As of early February 2026, the western United States is in the grip of a pervasive snow drought. Unlike traditional meteorological droughts defined strictly by a lack of falling precipitation, the current crisis is one of phase and storage. In many watersheds, particularly in the Pacific Northwest and the Northern Rockies, precipitation totals have tracked near or even above historical averages due to active atmospheric river sequences.² Yet, the mountains remain starkly bare. The snow line has retreated to unprecedented elevations, leaving mid-altitude basins—critical for spring runoff—exposed to rain and early melt.

This phenomenon represents a decoupling of precipitation from water availability. The "natural reservoir" of the snowpack is failing to fill, not necessarily because the sky is empty of moisture, but because the atmosphere is too warm to sustain the solid phase of water. The implications of this shift are profound, forcing a transition from a slow-release hydrological cycle to a "flashy" regime characterized by immediate runoff, increased flood risk in winter, and prolonged scarcity in summer.³

1.1 The Scale of the Anomaly

Data from the National Aeronautics and Space Administration (NASA) and the Natural Resources Conservation Service (NRCS) paint a stark picture of the 2026 winter. On January 4, 2026, satellite observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) indicated that snow covered only 141,416 square miles of the western United States.² This figure represents the lowest snow cover extent for that date in the entire MODIS record, which dates back to 2001.

Ground-based telemetry is equally concerning. The SNOTEL (Snow Telemetry) network, a system of automated sensors managed by the USDA, reported that over 80% of stations in Washington, Oregon, Colorado, Utah, Arizona, and New Mexico were experiencing snow drought conditions.² Snow drought in this context is defined statistically as Snow Water Equivalent (SWE) falling below the 20th percentile for the given date. In many basins, the situation is not merely below average; it is historic, with stations recording the lowest SWE in their operational history.⁵

1.2 Defining the Snow Drought Taxonomy

To understand the nuance of the 2025-2026 season, one must distinguish between the two primary classifications of snow drought, a taxonomy that has become increasingly relevant in academic discourse.

Dry Snow Drought This is the traditional manifestation of drought, occurring when total precipitation (rain plus snow) is significantly below average.¹ In this scenario, the snowpack is low simply because there is insufficient moisture input into the system. This type of drought is often driven by blocking high-pressure systems that divert storm tracks entirely away from the region, leaving the mountains dry and cold. Parts of the Desert Southwest and the Southern Rockies are currently experiencing this form of drought, exacerbated by the typical La Niña storm track displacement.⁶

Warm Snow Drought This more complex form occurs when precipitation is near or above average, but abnormally high temperatures prevent snow accumulation.⁶ This happens through two primary mechanisms: the partitioning of precipitation from snow to rain (the rising rain-snow transition line) and the premature melting of established snowpack during mid-winter warm spells.³ The winter of 2026 is a quintessential example of this phenomenon, particularly in the Pacific Northwest and the Sierra Nevada, where atmospheric rivers have delivered copious moisture, but tropical air masses have prevented accumulation at standard snow-line elevations.

The 2025-2026 water year is a complex hybrid of these two forms. The implications for water supply forecasting are distinct: in a dry snow drought, inflows are reduced all year. In a warm snow drought, streamflow arrives earlier than normal—often causing winter floods—but the prospects of a rich spring snowmelt season are limited, leaving reservoir managers with immediate flood risks followed by subsequent drought conditions.³

2. Atmospheric Architecture of the 2025-2026 Winter

The meteorological conditions of the 2025-2026 winter were not the result of a single stochastic event but rather a persistent, synoptic-scale configuration that favored warmth and blocked cold air intrusion. Understanding this architecture requires an analysis of the planetary wave patterns, the status of the El Niño-Southern Oscillation (ENSO), and the behavior of the Jet Stream.

2.1 The La Niña Signal and its Modification

Entering the winter, the Climate Prediction Center (CPC) and other forecasting bodies identified a persistent La Niña pattern in the equatorial Pacific. As of early 2026, the ENSO Alert System status remained at "La Niña Advisory".⁷ Classically, La Niña is associated with cooler-than-average sea surface temperatures (SSTs) in the central and eastern Pacific. This oceanic state typically influences the atmospheric circulation by pushing the polar jet stream northward, often resulting in wetter, cooler conditions for the Pacific Northwest and drier, warmer conditions for the Southwest (the "dipole" effect).⁸

However, the 2025-2026 La Niña did not behave according to the canonical textbook definition. While the equatorial SSTs remained below average (with the Niño-3.4 index hovering around -0.5°C), the atmospheric response was modulated by other modes of variability.⁷ Instead of a cold, snow-bearing flow into the Pacific Northwest, the jet stream was zonal and infused with subtropical moisture. The systems that impacted Washington and Oregon in December 2025 originated from latitudes much further south than is typical for a La Niña winter, leading to a "warm" expression of the ENSO phase.²

Forecasters noted that while La Niña persists, there is a 75% chance of a transition to ENSO-neutral during the January-March 2026 period.⁷ This transitioning state often leads to weaker teleconnections and more variable weather patterns, allowing other atmospheric drivers to dominate.

2.2 The Return of Persistent Ridging

A recurring feature of 21st-century western winters has been the development of persistent high-pressure ridges over the Northeast Pacific. In the winter of 2025-2026, a variation of this ridge established itself, creating an atmospheric block that fundamentally altered precipitation dynamics.

Research into western droughts highlights the critical role of synoptic-scale circulation features, particularly atmospheric blocking.¹⁰ In 2026, anomalously strong upper-level ridging and expansive surface high-pressure systems dominated the Pacific sector. These blocking patterns act as a barrier, diverting the coldest storms into the central continent while allowing only warm, modified marine air to penetrate the West Coast.¹⁰

Ridge Taxonomy and Impact Academic analysis of ridge patterns identifies three dominant types that influence western weather: the "North-ridge," "West-ridge," and "South-ridge".¹¹

• The South-ridge type, centered over the Southwest, has shown a positive trend in frequency and persistence in recent decades. In 2025-2026, the prevalence of this southern ridging contributed significantly to the regional drying and warming in the Colorado River Basin.

• The interaction of these ridges with atmospheric rivers (ARs) is crucial. While ridges generally block ARs, the specific positioning in late 2025 allowed moisture to undercut the ridge or ride over the top, delivering precipitation without the associated cold air support.¹¹

2.3 The "Warm Lid" and Radiative Forcing

The persistence of high pressure creates more than just a diversion of storms; it alters the radiative balance of the region. The air mass associated with the 2025-2026 ridging events was anomalously warm throughout the vertical column.¹² This "warm lid" prevented the formation of strong nocturnal inversions in the high valleys.

Typically, clear winter nights allow for radiative cooling that freezes the snow surface, creating a crust that protects the pack from sublimation and melting during the day. In 2026, however, overnight lows frequently remained near or above freezing.² Without this "hard freeze," the snowpack remained isothermal (at 0°C throughout its depth), making it highly susceptible to melt from even minor inputs of solar radiation or sensible heat from the air. This lack of refreezing is a critical failure point in the maintenance of the winter cryosphere.

The result was a December that saw near-record or record warmth across every major river basin in the West.² This thermal anomaly inhibited accumulation even when precipitation occurred, forcing a phase shift from snow to rain at elevations that would historically support a deep winter snowpack.

3. The Physics of Loss: Sublimation and Albedo Feedbacks

To fully grasp why the snowpack is disappearing, we must look beyond the macro-scale weather patterns to the micro-scale physics of the snow surface. The depletion of the 2026 snowpack is being accelerated by two powerful thermodynamic processes: Sublimation and the Snow-Albedo Feedback (SAF).

3.1 Sublimation: The Diffusive Loss

Sublimation is the phase transition where a substance passes directly from solid to gas, bypassing the liquid phase. In the context of snow drought, it represents the "disappearance" of water into the atmosphere, meaning it never contributes to soil moisture or streamflow.¹³

Mechanisms of Sublimation Recent academic work describes the sublimation of ice crystals as a process limited by the diffusive transport of vapor.¹⁴ The rate at which water molecules leave the ice lattice is driven by the gradient between the vapor pressure at the ice surface (which is saturated) and the vapor pressure of the ambient air.

• Vapor Pressure Deficit (VPD): The air masses associated with the 2026 high-pressure ridges were often characterized by high VPD. Even if the air was not "hot" in a summer sense, its capacity to hold water vapor was higher than the cold air typically found over a snowpack.

• Wind and Turbulence: Sublimation is significantly enhanced by wind, which scours the boundary layer of saturated air and replaces it with drier air.¹⁵ The storm tracks that grazed the region in January 2026 brought brisk winds that, combined with solar input, drove high sublimation rates.

Field campaigns such as the Surface Atmosphere Integrated Field Laboratory (SAIL) have quantified that sublimation can remove anywhere from 10% to 90% of snowfall from the system depending on conditions.¹⁵ In the arid basins of the Intermountain West during the 2026 winter, the combination of dry air and solar exposure likely pushed losses toward the upper end of this spectrum, effectively erasing the meager snowfall that did occur before it could melt and infiltrate the soil.

3.2 The Vicious Cycle: Snow-Albedo Feedback (SAF)

Perhaps the most critical mechanism driving the warm snow drought is the Snow-Albedo Feedback (SAF). Albedo is a measure of the reflectivity of a surface. Fresh, cold snow has an albedo of 0.8 to 0.9, meaning it reflects 80-90% of incoming solar radiation. This high reflectivity helps maintain low temperatures, preserving the snowpack.¹⁷

However, the warm conditions of 2025-2026 triggered a rapid degradation of albedo through distinct "trigger" mechanisms identified in cryospheric research ¹⁸:

1. The Accumulation Trigger An increase in air temperature increases the fraction of precipitation falling as rain. This results in less snowfall and a thinner snow cover. A thinner snowpack reveals the darker underlying ground sooner (or in patchy distribution), lowering the area-averaged albedo. This causes the surface to absorb more solar energy, warming the ground and melting the remaining snow from below—a positive feedback loop.¹⁸

2. The Precipitation Heat Flux Trigger When rain falls on snow, it delivers heat directly to the snowpack (sensible heat) and, perhaps more importantly, darkens the surface. Wet snow has a significantly lower albedo than dry snow. The liquid water acts as a lens, and the breakdown of the crystal structure reduces reflectivity. This triggers a feedback where the darker, wet snow absorbs more sunlight, accelerating melt.¹⁸

3. The Albedo Reset Trigger In a healthy winter, frequent storms deposit layers of fresh, bright snow, effectively "resetting" the albedo to high levels. In 2026, the long gaps between storms (dry spells) allowed the snow surface to age. Metamorphism causes ice grains to round and coarsen, which naturally lowers albedo. Furthermore, the lack of new snow allowed light-absorbing impurities (dust, soot, organic debris) to concentrate on the surface.¹⁹ The failure of the "albedo reset" meant that when the sun angle began to increase in late January, the snowpack was already dark and primed for rapid ablation.²⁰

3.3 The Energy Balance Shift

The shift from a cold winter to a warm snow drought fundamentally alters the surface energy balance. Table 1 illustrates the comparative energy fluxes.

Table 1: Comparative Snowpack Energy Balance (Hypothetical Basin)

Energy Component	Historical Cold Winter	2026 Warm Snow Drought	Impact on Snowpack
Net Shortwave Radiation	Low (High Albedo reflects ~85%)	High (Lower Albedo reflects ~60%)	Increased melting energy input
Longwave Radiation	Net Loss (Cooling to clear night sky)	Net Gain/Neutral (Cloud cover/Warm air)	Reduced night-time refreezing
Sensible Heat Flux	Negative (Air colder than snow)	Positive (Air warmer than snow)	Direct heat transfer from air to snow
Latent Heat Flux	Low (Minor evaporation)	High (Rapid Sublimation/Condensation)	Mass loss to atmosphere
Precipitation Heat Flux	Negligible (Snow falls at 0°C)	Significant (Rain falls at >2°C)	Rapid melt generation

This shift demonstrates that the snowpack is being attacked from multiple thermodynamic angles: from above by the sun (due to low albedo), from the air (sensible heat), and from the rain itself.⁵

4. Regional Hydro-Climatological Assessment

The impacts of this atmospheric setup were not uniform. The West is a vast topographic and climatic mosaic. The following analysis breaks down the snow drought by major hydro-regions, utilizing specific telemetry data from the current water year.

4.1 The Pacific Northwest: The Rain-on-Snow Paradox

The Pacific Northwest (Washington, Oregon, Idaho) typically serves as the reliable snow anchor during La Niña years. In late 2025, however, it became the epicenter of the Warm Snow Drought.

In December 2025, the region was battered by a series of atmospheric rivers. Precipitation totals were well above average—western Oregon and Washington saw rainfall totals exceeding 200% of normal in many basins.²¹ Mountain locations recorded over 20 inches of liquid precipitation during peak events. Yet, the SNOTEL data reveals a disconnect. Despite the abundance of moisture, snowpack metrics remained critically low.

The Mechanism of Loss The heavy rains fell on existing, early-season snowpack. When rain falls on snow, it transfers massive amounts of latent heat to the snowpack. As the water percolates through the snow, it warms the ice crystals to the melting point. If the rain is heavy enough, it can physically scour the snow away. This is exactly what occurred. The "natural reservoir" was bypassed; water that should have been stored for July runoff instead rushed immediately into river channels, causing winter floods while leaving the mountains bare.⁴

By January 4, 2026, Oregon faced the most severe conditions in the West. SNOTEL stations in the Oregon Cascades reported SWE values far below the 20th percentile.² The visual evidence was striking: ski resorts that typically operate on a base of 60-100 inches were forced to close or limit terrain to narrow strips of man-made snow.² The hydrological buffer of the Cascades had been effectively stripped away by the very storms that should have replenished it.

4.2 California and the Sierra Nevada: A Study in Whiplash

California’s hydrology is defined by extreme variability, often described as "weather whiplash." Following the historic snowpacks of previous years, 2026 presented a distinct regression, though with regional nuances.

Current Status (Early Feb 2026) Statewide, the snowpack stood at approximately 59% of the historical average for the date.²² The Department of Water Resources (DWR) manual survey at Phillips Station recorded a snow depth of 23 inches and a SWE of 8 inches—only 46% of the average for that location.²²

The disparity between the Northern and Southern Sierra was notable. The Northern Sierra, more exposed to the warm atmospheric rivers affecting the PNW, saw higher snow lines and more rain-on-snow events. The Southern Sierra, typically shielded by topography, fared slightly better in terms of percentage, but still faced deficits. For instance, the Southern Region was at 77% of normal to date, while the Northern Region was only at 44%.²³

Reservoir Operations and "First Flush" Crucially, California entered this snow drought with healthy reservoir storage, a legacy of previous wet years. Lake Oroville and Shasta Lake remained at above-average storage levels (127% and 122% of historical average, respectively) as of early February.²⁴ This creates a temporary "buffer year."

Adaptive management played a key role. DWR utilized operational flexibility regarding the "first flush" rule—a regulation that typically mandates pumping reductions to protect fish species when early winter storms swell river flows. By analyzing real-time data which showed that the triggers for these protections could be relaxed without harm to listed species, DWR was able to capture an additional 15,000 acre-feet of water supply in December and January.²⁶ This highlights the growing importance of regulatory agility in a climate where snowpack storage is unreliable.

4.3 The Colorado River Basin: The Structural Deficit

The Intermountain West (Utah, Colorado, Wyoming, New Mexico) faces a more existential threat. This region feeds the Colorado River, the lifeline for 40 million people.

Data Analysis The Upper Colorado Basin recorded severe deficits. January 2026 snow cover was among the lowest on record.⁵ SNOTEL data in the Upper Green River Basin (Wyoming) and the headwaters of the Colorado (western Colorado) showed SWE values struggling to reach 60-70% of the median.²⁷ The San Juan Basin in the south fared even worse, with some stations reporting near-zero accumulation.

Reservoir Status

Unlike the Sierra Nevada, the Colorado River system does not recover quickly. The massive reservoirs of Lake Powell and Lake Mead act as decadal integrators of climate. The low snowpack of 2026 exacerbates a long-term structural deficit.

• Lake Powell: As of January 2026, the lake was approximately 26% full (48% of average).²⁸ Projections for the end of the water year place the elevation near 3,535 feet, precariously close to the minimum power pool.²⁹

• Lake Mead: Standing at 33% full (60% of average) ²⁸, the reservoir continues to rely on shortages and conservation measures to maintain operations.

The lack of a "rescue winter" in 2026 heightens the urgency of interstate water negotiations and the finalization of the post-2026 operating guidelines.³¹ The 24-Month Study released by the Bureau of Reclamation confirms that operations will remain in the "Mid-Elevation Release Tier," limiting downstream releases to 7.48 million acre-feet.³²

5. Hydrological Forecasting and the "Runoff Efficiency" Problem

The translation of snow drought into hydrological reality is where the socioeconomic impacts become acute. The "Water Tower" model of the West relies on the timing of release. The 2026 snow drought is fundamentally altering this timing and the efficiency of the basin.

5.1 Runoff Forecasts

By February 1, 2026, water supply forecasts for the April-July runoff period were already grim. The Colorado Basin River Forecast Center (CBRFC) issued projections indicating significant deficits. Runoff forecasts for Utah and Colorado ranged from 55% to 80% of average.³³ While the Bear River basin was a rare bright spot (near 90%), the crucial tributaries of the Colorado—the Gunnison, the Green, and the San Juan—were trending toward severe shortages.⁸

5.2 The Runoff Efficiency Penalty

A critical, often overlooked factor is Runoff Efficiency—the ratio of snowmelt that actually makes it to the stream versus what is lost to the soil and atmosphere. In 2026, runoff efficiency is projected to be exceptionally low due to the Soil Moisture Deficit.

Following a hot, dry autumn in 2025, the soil moisture profiles in the Rockies were depleted.²⁸ When snowmelt eventually occurs in spring 2026, a significant percentage of the water will be absorbed by the thirsty soils before it ever reaches the stream network. This "soil tax" must be paid first. In a low snow year, the snowpack may be exhausted paying this tax, resulting in disproportionately low streamflow—a phenomenon observed in previous droughts where 70% snowpack yielded only 50% runoff.

Furthermore, the warm weather triggers vegetation to exit dormancy earlier. Trees and shrubs begin transpiring water earlier in the season, actively pumping moisture out of the soil that would otherwise contribute to groundwater recharge or runoff.¹³

5.3 Forecast Challenges: Bulletin 120

In California, the Department of Water Resources releases Bulletin 120 (B120), the definitive forecast for the state's water supply. The 2026 forecasts faced significant challenges due to the "no-analog" nature of the weather.

• QPF Errors: Forecasts rely on Quantitative Precipitation Forecasts (QPF). In dynamic years like 2026, over-forecasting precipitation (or missing the rain-snow line) can lead to significant errors in runoff timing predictions.³⁴

• Data Discrepancies: Discrepancies between different modeling systems (e.g., the CNRFC Snow-17 model vs. Airborne Snow Observatory data) can lead to uncertainty regarding the true volume of water stored in the high sierra.³⁴ In 2026, accurate data from airborne lidar surveys became more critical than ever to correct the biases of ground-based models that struggled to account for the patchy, high-elevation snow cover.

6. Ecological and Societal Fallout

The consequences of the 2026 snow drought ripple through every sector of Western society and the ecosystem.

6.1 The Recreation Economy

The ski industry acts as the economic "canary in the coal mine" for snow drought. In 2026, the impact was immediate. Resorts in Arizona and Southern California failed to open for the lucrative holiday season. In the Pacific Northwest and Colorado, major destinations operated with limited terrain, relying heavily on man-made snow.² This represents a significant economic contraction for mountain communities that rely on winter tourism revenue. The variability forces resorts to diversify summer operations, but the loss of the core winter product is difficult to offset.

6.2 Wildfire Potential: The "Spring Gap"

Snowpack acts as a fire suppressant. It keeps high-elevation fuels moist and delays the drying of the landscape. The early melt-out (or lack of accumulation) in 2026 sets the stage for a perilous fire season.

• Fuel Saturation vs. Curing: While the winter rains saturated dead fuels (logs, duff) in the Pacific Northwest, the lack of a lingering snow blanket means these fuels will be exposed to the sun and wind months earlier than usual.²¹

• Vegetation Growth: The warm, wet conditions in lower elevations (the rain-on-snow zones) stimulated the growth of fine fuels (grasses). As these grasses cure (dry out) in the spring, they will provide a continuous, highly flammable fuel bed.²¹

• The Outlook: Fire behavior analysts predict that significant fire potential is expected to remain normal through April due to the wet soils, but the "spring gap"—the period between snowmelt and summer monsoons—will be extended. The deficient snowpack reduces confidence in the late-spring safety, likely allowing high-elevation fires to burn earlier in the year.²¹

6.3 Agriculture and Irrigation

For the agricultural valleys of the West, the snow drought signals a year of potential cutbacks. Water users in areas impacted by below-normal snowpack—particularly those with junior water rights—are being warned of reduced allotments.²⁸ This necessitates a shift toward groundwater pumping, further stressing aquifers that are already critically over-drafted, particularly in California's San Joaquin Valley. The reliance on the "buffer" of reservoir storage in 2026 may save the current crop year, but it depletes the insurance policy for 2027.

7. Conclusion: The New Normal is Now

The winter of 2025-2026 is not merely a statistical outlier; it is a manifestation of the structural shift predicted by decades of climate science. The West is transitioning from a snow-dominated hydrological regime to a rain-dominated one. The "Snow Drought" is no longer a theoretical risk but a recurring reality.

The convergence of a non-canonical La Niña, persistent atmospheric ridging, and background warming trends created a perfect storm for snow loss. The mechanisms of sublimation and albedo feedback acted as force multipliers, stripping the mountains of their storage capacity even in basins that received precipitation.

While reservoir carryover may blunt the immediate impact for some urban users in 2026, the buffer is finite. The hydrological deficit accumulating in the Colorado River Basin and the groundwater aquifers of the West cannot be solved by a single wet month. The "Warm Snow Drought" demands a fundamental reimagining of western water infrastructure. We can no longer rely on the mountains to passively store our water. The era of the "free reservoir" is ending, and the burden of storage and management is shifting entirely to human-engineered systems—systems that must adapt to the volatility of the Anthropocene through tools like Forecast-Informed Reservoir Operations (FIRO) and aggressive conservation.

Key Findings for Water Year 2026:

• Taxonomy: A hybrid event featuring "Warm Snow Drought" in the PNW/Sierra and "Dry Snow Drought" in the Southwest.

• Status: Record low snow cover (lowest Jan 4 in MODIS record).²

• Driver: Atmospheric ridging and warm temperatures partitioned precipitation into rain and drove high sublimation rates.¹¹

• Outcome: Reduced runoff efficiency due to soil moisture deficits and early fire risk in high elevations.²¹

The "brown mountains" of 2026 serve as a stark visual metric of a climate system in flux, a warning that the reliable patterns of the past are poor guides for the water security of the future.

8. Detailed Regional Data Appendix

Table 2: Snow Water Equivalent (SWE) by Region (Jan 2026)

Data sourced from USDA NRCS SNOTEL Network and California DWR.²

Region	Basin Example	SWE % of Median (approx.)	Dominant Driver
Pacific Northwest	Willamette (OR)	30-40%	Warmth / Rain-on-Snow / Scouring
Northern Rockies	Upper Snake (ID/WY)	60-70%	Mixed precipitation / Early melt
Central Rockies	Upper Colorado (CO)	55-65%	Ridging / Dryness / Soil Deficit
Great Basin	Provo/Weber (UT)	50-60%	Blocking High Pressure
Sierra Nevada	Central Sierra (CA)	59%	Warm Storms / High Snow Levels
Southwest	Verde/Salt (AZ)	<25%	La Niña Dryness / Sublimation

Table 3: Major Reservoir Status (Feb 1, 2026)

Data sourced from US Bureau of Reclamation and California DWR.²⁵

Reservoir	State	% of Capacity	% of Historical Avg	Context
Lake Oroville	CA	~70%	127%	Strong carryover from '23/'24; Flood ops in Jan.
Shasta Lake	CA	~80%	122%	Strong carryover; "First Flush" flexibility used.
Lake Powell	AZ/UT	~26%	48%	Elevation ~3535 ft; Structural long-term deficit.
Lake Mead	NV/AZ	~33%	60%	Stabilization via shortages and 24-Month Study.
Elephant Butte	NM	~9%	29%	Critically low / Rio Grande drought.

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