Alto, CA Live Doppler Radar
Live radar for Alto, Marin County: every NWS radar combined, rain, snow and ice colors, flash-flood risk, storm tracks and official warnings.
What weather hits Alto?
Since 1996, the National Weather Service has logged river or areal flooding on 60 days in the North Bay Interior Valleys forecast zone and Marin County — the most common reported hazard around Alto, mostly in January and February. Next come debris flows (19 days) and excessive heat (19 days).
| Hazard | Days reported | Most recent | Worst on record |
|---|---|---|---|
| Flooding | 60 | Dec 2025 | Jan 1, 2006 · $108 million damage |
| Debris flows | 19 | Jan 2021 | Apr 1, 2006 · 1 death · $34 million damage |
| Excessive heat | 19 | Mar 2026 | Jul 21, 2006 · 1 death |
| Coastal flooding | 16 | Jan 2026 | — |
| Flash flooding | 15 | Feb 2017 | Dec 11, 2014 · $4.0 million damage |
| High winds | 12 | Mar 2023 | Mar 19, 2011 · 1 death · $35,000 damage |
| Wildfires | 6 | Jun 2024 | Jun 16, 2024 · $10 damage |
| Damaging thunderstorm winds | 4 | Dec 2025 | — |
Source: NOAA NCEI Storm Events Database, 1996–2026 (the latest year is partial). A "day" is a date with at least one report in the North Bay Interior Valleys forecast zone and Marin County; damage is as reported, not adjusted for inflation.
Which radars cover Alto?
The closest NEXRAD Doppler radar is KDAX (Sacramento, CA), about 61 miles northeast. Radar beams climb as they travel, so the height of the lowest scan over town decides how low in a storm the radar can see.
| Radar | Distance | Lowest beam over Alto | View |
|---|---|---|---|
| KDAX Sacramento, CA | 61 mi northeast | 4,700 ft | Good — most storms and steady rain or snow show clearly |
| KMUX San Francisco, CA | 62 mi south-southeast | 4,800 ft | Good — most storms and steady rain or snow show clearly |
| KBBX Beale AFB, CA | 120 mi north-northeast | 12,700 ft | Limited — the beam overshoots the lowest part of storms |
Beam height is the center of the 0.5° scan above the radar, with standard refraction. Mountains near a radar can block it further.
Tornado & hail history near Alto
Since 1950, NOAA has recorded 4 tornadoes within 25 miles of Alto. Most came in December and April. The strongest was an F1 on March 20, 2005, which passed about 18 miles south-southeast of town.
Hail: 1 report of 1-inch or larger hail within 25 miles since 1955; the largest was 1.00-inch hail on March 4, 1996.
Source: NOAA Storm Prediction Center — tornadoes 1950–2025, hail 1955–2025. Distances are to each tornado's track; ratings before February 2007 use the original Fujita scale.
On TALON you get Alto's live radar loop, rain/snow/ice colors, flash-flood risk, storm tracks with arrival times and NWS warnings free; close-up radar and rotation detection are part of TALON Pro.
Alto radar FAQ
Where is the nearest weather radar to Alto, CA?
KDAX (Sacramento, CA), about 61 miles northeast. KMUX (San Francisco, CA) is 62 miles away and also covers the area.
How often does Alto flood?
Since 1996 the National Weather Service has logged river or areal flooding on 60 days in the North Bay Interior Valleys forecast zone and Marin County. TALON's free flash-flood risk layer shows, every 2 minutes, how close the rain that has fallen is to what it takes to flood — turn it on under Layers.
Is TALON's radar for Alto free?
Yes — the US radar loop, rain/snow/ice colors, flash-flood risk, storm tracks and NWS warnings are free in any browser. Close-up radar, rotation detection and longer forecasts are part of TALON Pro.
Should I rely on radar for my safety?
No app replaces official warnings. When the National Weather Service issues a warning for Alto, follow it right away — see watch vs. warning.
Radar for nearby towns
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