Portola Valley, CA Live Doppler Radar
Live radar for Portola Valley, San Mateo County: every NWS radar combined, rain, snow and ice colors, flash-flood risk, storm tracks and official warnings.
What weather hits Portola Valley?
Since 1996, the National Weather Service has logged river or areal flooding on 41 days in the Santa Cruz Mountains forecast zone and San Mateo County — the most common reported hazard around Portola Valley, mostly in December and February. Next come high winds (38 days) and debris flows (15 days).
| Hazard | Days reported | Most recent | Worst on record |
|---|---|---|---|
| Flooding | 41 | Jan 2026 | Jan 1, 2006 · $5.0 million damage |
| High winds | 38 | May 2026 | Feb 27, 2006 · 1 death |
| Debris flows | 15 | Jan 2023 | Apr 4, 2006 · $13 million damage |
| Flash flooding | 14 | Jan 2026 | Feb 3, 1997 · 1 death |
| Damaging thunderstorm winds | 12 | Dec 2025 | Oct 19, 2004 · $50,000 damage |
| Wildfires | 5 | Jan 2021 | Aug 16, 2020 · 1 death |
| Excessive heat | 3 | Mar 2026 | — |
| Heavy snow & winter storms | 3 | Feb 2023 | Feb 24, 2023 · $10 damage |
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 Santa Cruz Mountains forecast zone and San Mateo County; damage is as reported, not adjusted for inflation.
Which radars cover Portola Valley?
The closest NEXRAD Doppler radar is KMUX (San Francisco, CA), about 23 miles southeast. 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 Portola Valley | View |
|---|---|---|---|
| KMUX San Francisco, CA | 23 mi southeast | 1,400 ft | Excellent — the lowest scan sees close to the ground |
| KDAX Sacramento, CA | 84 mi north-northeast | 7,400 ft | Fair — the beam can pass over shallow snow and low-level rotation |
| KBBX Beale AFB, CA | 151 mi north-northeast | 18,300 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 Portola Valley
Since 1950, NOAA has recorded 11 tornadoes within 25 miles of Portola Valley, 2 of them EF2/F2 or stronger. Most came in January and March. The strongest was an F2 on May 5, 1998, which touched down about 11 miles east of town. The most recent was an EF1 on December 14, 2024, which touched down about 24 miles south-southeast of town.
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 Portola Valley'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.
Portola Valley radar FAQ
Where is the nearest weather radar to Portola Valley, CA?
KMUX (San Francisco, CA), about 23 miles southeast. KDAX (Sacramento, CA) is 84 miles away and also covers the area.
How often does Portola Valley flood?
Since 1996 the National Weather Service has logged river or areal flooding on 41 days in the Santa Cruz Mountains forecast zone and San Mateo 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 Portola Valley 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 Portola Valley, follow it right away — see watch vs. warning.