Northern California Water Resources Dashboard
Northern California
Water Resources Dashboard
Snowpack, reservoir, and lake level tracking — comparing 2026 conditions against 20 years of historical data with season-end projections.
2026 Season Overview
The 2025–26 water year in Northern California tells a story of dramatic swings — a pattern scientists call weather whiplash. The season opened slowly with scant October–November precipitation, then atmospheric rivers in late December sent reservoir levels surging. A bone-dry January eroded snowpack gains, dropping the statewide pack from 89% to 59% of average in three weeks. Mid-February brought the third-snowiest 5-day period on record at the UC Berkeley Central Sierra Snow Lab (111 inches), pushing statewide snowpack back toward ~97% of average by late February.
Critically, the Northern Sierra remains the weak link — running around 44–70% of normal — while the Central and Southern Sierra recovered more robustly. Reservoirs are in strong shape at 126% of historical average, buoyed by three consecutive above-average water years that replenished the state's surface water infrastructure.
The transition from La Niña to ENSO-neutral conditions (60% probability Feb–April 2026) introduces uncertainty. Forecasts favor above-normal precipitation into early March before shifting to equal odds.
Lowest NorCal region
Recovered in Feb
Above normal
Near normal
Snowpack Deep Dive — 2026 vs. 20-Year History
Northern Sierra: The Laggard
The Northern Sierra has been the most troubled region. Early January found it at just 16% of average — one of the worst readings in 20 years. Despite December atmospheric rivers and February storms, the region sits around 70% of average. Warm storm tracks pushed snow levels higher in elevation, leaving lower stations with depleted packs.
Central Sierra: A Recovery Story
After dipping to 59% of average by late January, massive mid-February storms (111 inches in 5 days at the Snow Lab) brought high-elevation sites to near or above average. Phillips Station recorded 23 inches depth with 8 inches SWE on January 30 — 46% of average. Post-February storms, the region is now estimated near 97% of average.
20-Year Historical Context
Northern California snowpack has displayed increasing volatility. The 2022–23 season produced over 200% of April 1 average, while 2020–21 and 2013–14 were severe snow drought years. The current whiplash pattern reflects a broader trend toward extreme swings attributed to warming temperatures and shifting storm tracks.
Reservoir & Lake Levels — February 2026
Reservoirs entered 2026 in excellent shape from three consecutive above-average water years. Despite uneven snowpack, they remain at 126% of historical average. Direct rainfall has been substantial even when snowpack faltered.
Key Highlights
Lake Shasta (4.55M AF) — ~81% capacity, 113% of hist avg. Rose 36 feet in three weeks during Dec storms. Lake Oroville (3.54M AF) — ~80%, 128% of avg. Spillway activated Jan. Folsom Lake (977K AF) — ~56%, 116% of avg. Trinity Lake (2.45M AF) — ~84%, recovered from 38% in 2024.
The dry January did not significantly impact reservoir levels because December storms had already deposited massive runoff directly into reservoirs.
Season-End Projections & Forecast
Remaining Season Outlook
ENSO-neutral transition (60% probability) introduces uncertainty. Forecasts favor above-normal precipitation through early March, then equal odds. Weather West (Feb 24) notes warm/dry conditions returning by early March.
March typically contributes 20–25% of the Sierra's total season snow. With the warmest winter on record for much of the western U.S., late storms are more likely to produce rain than snow at lower elevations.
Projected April 1 Snowpack
| Scenario | Probability | Statewide Apr 1 SWE | N. Sierra Apr 1 SWE | Notes |
|---|---|---|---|---|
| Optimistic | 25% | 90–100% | 75–85% | Sustained storms through March |
| Most Likely | 50% | 70–85% | 55–70% | Mixed, warm spells persist |
| Pessimistic | 25% | 55–70% | 40–55% | Warm ridge, minimal late snow |
Projected Reservoir End-of-Season
Reservoirs are well-positioned regardless. Even pessimistically, major reservoirs should reach 80–90% by late spring.
| Reservoir | Current (Feb '26) | Projected Peak | vs. 20-Yr Avg |
|---|---|---|---|
| Lake Shasta | ~81% | 90–98% | Above avg |
| Lake Oroville | ~80% | 92–100% | Above avg |
| Folsom Lake | ~56% | 75–90% | Near to above |
| Trinity Lake | ~84% | 88–95% | Well above |
| Bullards Bar | ~73% | 85–95% | Above avg |
| Lake Tahoe | Near max | At/near max | Above avg |
Key Takeaway
Northern California's 2026 outlook is cautiously positive. Uneven snowpack in the Northern Sierra is a concern, but reservoir buffers from three surplus years provide significant insurance. The State Water Project allocation stands at 30% of requested supplies, with increases possible depending on March conditions.