An unseasonably cold air mass combined with clearing skies to allow sub-freezing temperatures to develop in the early morning on this date.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS MFR wrote it up.
An unseasonably cold air mass combined with clearing skies to allow sub-freezing temperatures to develop in the early morning on this date.
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 Apr 12, 2:59 AM PST, 1 minute earlier.
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</html>The national radar mosaic for the moment the first event began.
3 frost/freeze. Local standard time, as filed.
Reported low temperatures ranged from 29 to 33 degrees.
Reported low temperatures ranged from 28 to 30 degrees.
Reported low temperatures ranged from 22 to 31 degrees.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2011Every state in 2011This day in weather historyWarnings in Oregon, April 2011
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: 284146, 284150, 284152.