Heavy Snow — South Central Siskiyou County, California

2010-01-20 to 2010-01-21 · South Central Siskiyou County, California

Event narrative

A spotter ESE Mount Shasta City reported 10 inches of snow in 9.5 hours between 20/0100 and 20/1030 PST, then 10-12 inches in 12 hours ending at 21/0030 PST. Later he reported a total accumulation of 48 inches of snow in 41.5 hours between 19/1700 and 21/1030 PST. A spotter 4SW Weed reported 24 inches of snow between 19/1600 and 20/1100 PST. A spotter ESE Mount Shasta City reported 24 inches of snow in 48 hours between 18/2000 and 20/2000 PST. A spotter 4SSW Weed reported 18 inches of snow in 10.5 hours between 20/1030 and 20/2100 PST. A spotter 3NW Mount Shasta City reported 33 inches of snow in 48 hours between 18/2100 and 20/2100 PST. A spotter 6NW Mount Shasta City reported 7 inches of snow in 12 hours between 21/1900 and 22/0700 PST. A spotter 4SW Weed reported 22 inches of snow in 16 hours between 21/1800 and 22/1000 PST. A spotter 2SW Mount Shasta City reported 16-18 inches of snow in 24 hours between 20/1030 and 21/1030 PST with 24 inches of snow on the ground. A spotter 1NE Mount Shasta City reported 18 inches of new snow overnight (1/20-21/10) and 48 inches total. Power was out and numerous trees were down. Power in some areas was out 4-5 days and avalanche warnings were issued for Mount Shasta. The cooperative observer in Mount Shasta City reported 17 inches of snow in 21 hours between 19/2300 and 20/2000 PST, then 10 more inches of snow in 24 hours between 20/2000 and 21/2000 PST. The cooperative observer in McCloud reported 10.5 inches of snow in 24 hours between 20/0800 and 21/0800 PST.

Wider weather episode

A continued unsettled pattern remained over the CWA in association with a very active upper level jet and El Nino pattern. The California portion of the Medford CWA was on the northern fringe of the area of heavy precipitation. Significant snowfall accumulations were reported for northern California as upslope flow prevailed across the area. This snow was very wet...about a 6 to 1 snow ration...and this caused many broken trees and branches to fall into power lines...resulting in widespread power outages. Overall the 1/19-21/10 snowfall in Mt. Shasta City was 39 inches...the greatest 3 day total since 1970. Widespread power outages began on 1/19/10 (Tuesday). Nearly 9000 Pacific Power customers were without power at the peak of the storm. By 1/23/10 (Saturday), 1260 customers were still without power. Virtually all customers had power back by 1/25/10 (Monday). Siskiyou county, along with other counties in the state, was declared a disaster area due to this storm.

Source: NOAA Storm Events Database, event_id 203520. Narrative written by the NWS forecast office that issued the report.