Flash Flood Warning 8, NWS San Francisco Bay Area, CA

Issued

Jan 27, 2021, 12:33 PM PST (20:33 UTC)

Expired

Jan 27, 2021, 6:30 PM PST

In force

6 hr

Issued by

NWS San Francisco Bay Area, CA

Area

Storm-based polygon

Flood severity

None

Counties San Mateo County, CA, Santa Cruz County, CA

The San Francisco radar (KMUX), 26 km from the middle of the area, began a volume at 20:36 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

544 
WGUS56 KMTR 272033
FFWMTR
CAC081-087-280230-
/O.NEW.KMTR.FF.W.0008.210127T2033Z-210128T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
1233 PM PST Wed Jan 27 2021

The National Weather Service in San Francisco has issued a

* Flash Flood Warning for...
  The CZU Lightning Complex burn area in...
  Southeastern San Mateo County in northern California...
  Northwestern Santa Cruz County in northern California...

* Until 630 PM PST.

* At 1233 PM PST, Doppler radar indicated thunderstorms producing 
  heavy rain about to move over the CZU Lightning Complex Burn Area. 
  Flash flooding is expected to begin shortly.

Excessive rainfall over the burn area will result in debris flow 
moving through the CZU Lightning Complex burn area. The debris flow 
can consist of rock, mud, vegetation and other loose materials.

  HAZARD...Flash flooding caused by thunderstorms in and around
           the CZU Lightning Complex Burn Area.

  SOURCE...Doppler radar.

  IMPACT...Flooding of areas in and around the CZU Lightning
           Complex Burn Area.

* Some locations that will experience flash flooding include...
  Boulder Creek.

This is a life threatening situation for people in or near the CZU 
Lightning Complex burn area. Some drainage basins impacted include...
Butano Creek...Gazos Creek...Waddell Creek...Scott Creek...Big Creek 
and Boulder Creek.
 
Heavy rainfall will cause flash flooding of creeks and streams from 
the CZU Lightning Complex burn area downstream. Anyone living or 
traveling on roads in the CZU Lightning Complex burn area or along 
secondary roads like Swanton Road...Jamison Creek Road...and Hwy 9 
from Boulder Creek to Brookdale...should be alert for possible road 
problems due to erosion...debris flows...rockfalls and debris. 
Roadways and bridges may be washed away in places.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life-threatening situation. If you observe movement of 
soils move to higher ground immediately.

&&

LAT...LON 3714 12234 3720 12235 3727 12231 3725 12222
      3718 12214 3713 12213 3714 12215 3711 12211
      3704 12209 3702 12211 3703 12213 3706 12214
      3707 12212 3708 12214 3707 12214 3703 12220
      3711 12227

FLASH FLOOD...RADAR INDICATED

$$

Palmer

689 
WGUS76 KMTR 280223
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
623 PM PST Wed Jan 27 2021

CAC081-087-280233-
/O.EXP.KMTR.FF.W.0008.000000T0000Z-210128T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Mateo CA-Santa Cruz CA-
623 PM PST Wed Jan 27 2021

...FLASH FLOOD WARNING FOR THE CZU LIGHTNING COMPLEX BURN AREA WILL 
EXPIRE AT 630 PM PST THIS EVENING FOR SOUTHEASTERN SAN MATEO AND 
NORTHWESTERN SANTA CRUZ COUNTIES...

The heavy rain has ended, but light to moderate rain will continue.  
Additional rain showers are expected overnight. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

A Flash Flood Watch remains in effect until 400 PM PST Thursday for 
a portion of western California.

LAT...LON 3714 12234 3720 12235 3727 12231 3725 12222
      3718 12214 3713 12213 3714 12215 3711 12211
      3704 12209 3702 12211 3703 12213 3706 12214
      3707 12212 3708 12214 3707 12214 3703 12220
      3711 12227

$$

MM

Flash Flood Warnings in California, 2021Every flash flood warning in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.