Heavy Snow in California, February 4 to 5, 2010

Name: Heavy Snow in California, February 4 to 5, 2010
Start: 2010-02-04T20:10
End: 2010-02-05T04:40
Location: California

February 4 to 5, 2010 · NWS MFR · 2 events in 2 counties and zones

A strong low pressure system moved across the Pacific Northwest with strong upslope flow across Northern California which resulted in heavy snow accumulations.

Where it happened

Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
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Hail
Winter weather
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Cold
Fire, smoke and dust
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Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS MFR wrote it up.

A strong low pressure system moved across the Pacific Northwest with strong upslope flow across Northern California which resulted in heavy snow accumulations.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Medford, OR wrote its last area forecast discussion before the first event at Feb 4, 2:56 PM PST, 5 hours 14 minutes earlier.

Area forecast discussion, Feb 4, 2:56 PM PST, 5 hours 14 minutes before

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Hazardous weather outlook, Feb 4, 3:20 PM PST, 4 hours 50 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

2 heavy snow. Local standard time, as filed.

Heavy Snow, South Central Siskiyou County

When: February 4, 8:10 PM PST to February 5, 4:40 AM PST
Where: South Central Siskiyou County forecast zone
Reported by: Trained Spotter
Coordinates: 41.593, -122.540 (the zone’s center; the record gives no point)

A spotter 4SW Weed reported 8 inches of snow from 24/1500 PST to 25/0600 PST. Castle Lake weather station at 5900 feet 5W Dunsmuir reported 20 inches of snow from 04/0800 PST to 05/0800 PST. A report from the Snowman Summit station at elevation 4478 feet measured 2.62 inches of liquid precipitation through the entire warning period with 2.97 inches measured between 04/1040 PST and 05/0400 PST. Using a 6 to 1 snow ratio for this wet type snow event, this translates to 18 inches of snow in less than 18 hours.

Heavy Snow, North Central & Southeast Siskiyou County

When: February 4, 8:10 PM PST to February 5, 4:40 AM PST
Where: North Central & Southeast Siskiyou County forecast zone
Reported by: Trained Spotter
Coordinates: 41.593, -122.540 (the zone’s center; the record gives no point)

A report from the Snowman Summit station at elevation 4478 feet measured 2.62 inches of liquid precipitation through the entire warning period with 2.97 inches measured between 04/1040 PST and 05/0400 PST. Using a 6 to 1 snow ratio for this wet type snow event, this translates to 18 inches of snow in less than 18 hours. Even though this station is in CAZ082 we are making the assumption that Heavy Snow Warning criteria was met for CAZ083 as well, since CAZ083 has similar geography to CAZ082, but hardly any people.

What these are

Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2010 Every state in 2010 This day in weather history Warnings in California, February 2010

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 205120, 205121.