Sunday, January 8, 2017

NWS #CAStorm update: This is only Round One


The latest from the National Weather Service:
The atmospheric river is impacting California today with heavy precipitation, high snow levels and soils that are already saturated from recent storms. Majority of the precipitation will fall as rain in the mountains as snow levels are above 8000 feet. We are currently getting reports of flooding across the foothills and valley with additional significant flooding expected. This is more precipitation than we've seen in the past decade...areas may flood that haven't seen impacts for several years. Intensity will decrease Monday, but we do not expect much of a break before the next storm on Tuesday-Wednesday. Besides flooding, the other major concern is heavy snow, especially across the Sierra between Monday through Wednesday. This snow will cause significant travel hazards for mountain areas. Beyond Wednesday, additional precipitation is possible at the end of the week or over the weekend, but there is low confidence in timing details at this point. Keep in mind that flooding will take several days to recede in some areas after the rain stops.

Impacts
Widespread flooding of urban areas, roadways, small streams, and main stem rivers
Enhanced downstream river flooding from flood control releases on numerous Sierra reservoirs
Mud and debris flows on burn scars from past 4 years
Rock and mudslides on mountain roadways
Downed trees and power outages from wind and saturated soils
Mountain travel hazards (chain controls, delays, accidents, closures, white-out conditions)

Forecast Confidence
High
Medium in timing/amounts for additional storms past Monday

Timing and Strength
Heaviest Precipitation expected today
Snow levels above 8000 ft so much of this will fall as rain
Thunderstorms possible
Rivers and Streams
Rising water levels Today - next week
Several points reach flood stage today. River forecasts at http://www.cnrfc.noaa.gov/
Streams and creeks that are free-flowing (no dams) will bear close watching; we could see impacts in those areas unseen for years
Additional rises expected from Tuesday-Wednesday storm
Winds Today
Valley gusts 30-50 mph
Mountain ridge-top gusts 45 to 60 mph
Snow Monday-Wednesday
Snow levels drop back below pass levels early Monday around 4000-5000 ft
Sierra snow amounts could peak between 3-5 feet
Wet pattern continues past Monday
Another wet storm system Tuesday-Wednesday
Additional precipitation may arrive sometime towards the end of the week
Continued flood threat
The East Valley Times has published a list of sandbag locations throughout Shasta County and reports that PG&E is urging caution as north state reservoirs spill and rivers run high.

If you are a grower or ag organization representative and you have been impacted or know of impacts from the storm, please contact me at thearden@capitalpress.com or timhearden@gmail.com.

For updates on the rain and snow and their impacts, keep watch here and at CapitalPress.com.

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