On the evening of the 28th into the early morning hours of the 29th, a low-level jet developed over the Idaho Panhandle ahead of a strong low pressure system tracking along the Washington / Canadian Border. Through midnight, the strong low-level winds remained decoupled from the valley floors with high wind gusts measured only along exposed ridgetops.
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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 OTX wrote it up.
On the evening of the 28th into the early morning hours of the 29th, a low-level jet developed over the Idaho Panhandle ahead of a strong low pressure system tracking along the Washington / Canadian Border. Through midnight, the strong low-level winds remained decoupled from the valley floors with high wind gusts measured only along exposed ridgetops. Around midnight, a line of thunderstorms developed along the trailing cold front. A combination of descending air within the thunderstorm downdrafts along with terrain channeling was thought to be responsible for mixing the stronger winds aloft down to some valley locations within the Central Panhandle Mountains of Idaho. There were two reports of large trees toppled by these winds. Wind gusts within the zone ranged from 30 to 60 miles per hour with gusts near 60 miles per hour thought to be present where the trees were downed.
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 Spokane, WA wrote its last area forecast discussion before the first event at Dec 28, 9:35 PM PST, 2 hours 55 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 935 PM PST Wed Dec 28 2011 .SYNOPSIS...A series of storm systems will move through the Pacific Northwest this week. A very wet storm will arrive tonight and will bring valley rain and moderate high mountain snow. Another storm will bring heavier mountain snow and more valley rain on Friday. A general drying trend will arrive for the weekend...with more storms possible next week. && .DISCUSSION... Update for tonight: Cameras and observations around the Okanogan Valley and even Methow Valley indicate all valley locations are above freezing with no noticeable snow reaching the ground in any location. The only place with even an outside shot of seeing a flake or two hitting the ground is around Winthrop, where temperatures are currently running a saturated 34F. While the majority of the precipitation has probably already fallen in these locations, snow levels were raised for the remainder of the evening so most locations indicate only rainfall in the forecast, except around Winthrop, where a mix was kept. The rest of the forecast still looks largely on target as a cold front traverses Washington overnight with stronger and a bit more westerly flow picking up overnight into Thursday morning. As 850 mb flow turns more westerly, the rain shadow east of the Cascades will become much more prevalent overnight, which is well depicted in the forecast from Wenatchee to Moses Lake, so few other changes were made. /Fries && .AVIATION... 06Z TAFs: A cold front is pushing east past KGEG/KPUW this evening and will slide east of the area within the next few hours. Mixing behind the front as the vertical profile destabilizes actually increases in its immediate wake, allowing gusty WSW winds to hit almost all sites for at least a period overnight into Thursday morning. In addition, the more unstable profile will allow for showery precipitation to continue overnight, albeit with freezing levels still running rather high. The only problematic element in the forecast is the possiblity of wind shear. If the low levels manage to decouple from the larger atmosphere, some fairly impressive LLWS is possible around KGEG/KPUW/KCOE/KSFF, however at this time it seems more likely that winds will stay up at the surface. /Fries && .PRELIMINARY POINT TEMPS/POPS... Spokane 38 43 39 44 29 33 / 80 10 100 100 20 10 Coeur d'Alene 38 43 36 45 28 35 / 90 20 100 100 30 10 Pullman 42 47 41 47 30 37 / 100 20 100 100 30 10 Lewiston 45 51 42 52 34 41 / 90 20 90 90 10 10 Colville 35 44 32 39 27 31 / 70 10 100 100 30 10 Sandpoint 39 42 34 40 29 32 / 100 40 100 100 50 20 Kellogg 38 40 32 39 26 30 / 100 80 100 100 90 30 Moses Lake 38 49 37 47 32 37 / 40 10 80 60 10 0 Wenatchee 37 46 34 45 31 33 / 50 10 90 40 20 0 Omak 33 40 32 40 25 32 / 50 10 90 50 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SPOKANE WA 242 PM PST WED DEC 28 2011 WAZ042-291500- EAST SLOPES NORTHERN CASCADES- 242 PM PST WED DEC 28 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL WASHINGTON. .DAY ONE...THIS AFTERNOON AND TONIGHT NO HAZARDOUS WEATHER EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THERE IS THE POTENTIAL FOR A ROUND OF WET...HEAVY SNOW THURSDAY NIGHT INTO FRIDAY MORNING OVER THE EAST SLOPES OF THE NORTHERN CASCADES. PLACES LIKE WINTRHOP...MAZAMA...PLAIN...AND STEHEKIN HAVE THE POTENTIAL TO GET 4 TO 7 INCHES OF WET SNOW. NEARBY MOUNTAIN LOCATIONS WILL LIKELY GET MORE THAN A FOOT OF NEW SNOW BETWEEN THURSDAY NIGHT AND FRIDAY. IDZ001>004-026-027-WAZ031>038-041-043-044-291500- NORTHERN PANHANDLE-COEUR D'ALENE AREA-IDAHO PALOUSE- CENTRAL PANHANDLE MOUNTAINS-LEWISTON AREA- LEWIS AND SOUTHERN NEZ PERCE COUNTIES-NORTHEAST BLUE MOUNTAINS- LOWER GARFIELD AND ASOTIN COUNTIES-WASHINGTON PALOUSE- MOSES LAKE AREA-UPPER COLUMBIA BASIN-SPOKANE AREA- NORTHEAST MOUNTAINS-OKANOGAN HIGHLANDS-WENATCHEE AREA- OKANOGAN VALLEY-WATERVILLE PLATEAU- 242 PM PST WED DEC 28 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH IDAHO... NORTH CENTRAL IDAHO...CENTRAL WASHINGTON...EAST CENTRAL WASHINGTON...NORTH CENTRAL WASHINGTON...NORTHEAST WASHINGTON AND SOUTHEAST WASHINGTON. .DAY ONE...THIS AFTERNOON AND TONIGHT NO HAZARDOUS WEATHER EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY FRIDAY AND FRIDAY EVENING HAVE THE POTENTIAL TO BE WINDY OVER THE COLUMBIA BASIN...THE PALOUSE...THE WEST PLAINS...AND THE WATERVILLE PLATEAU. GUSTS IN THE 35 TO 45 MPH RANGE WILL BE POSSIBLE.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SPOKANE WA
1207 AM PST THU DEC 29 2011
IDZ002>004-WAZ033-290930-
SHOSHONE ID-WHITMAN WA-BENEWAH ID-LATAH ID-KOOTENAI ID-SPOKANE WA-
1207 AM PST THU DEC 29 2011
THE NATIONAL WEATHER SERVICE IN SPOKANE HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
SOUTHEASTERN SPOKANE COUNTY IN EASTERN WASHINGTON
NORTHEASTERN WHITMAN COUNTY IN EASTERN WASHINGTON
SOUTHEASTERN KOOTENAI COUNTY IN THE PANHANDLE OF IDAHO
NORTHERN LATAH COUNTY IN THE PANHANDLE OF IDAHO
BENEWAH COUNTY IN THE PANHANDLE OF IDAHO
SOUTHERN SHOSHONE COUNTY IN THE PANHANDLE OF IDAHO
UNTIL 130 AM PST
AT 1158 PM PST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A NARROW LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS ALONG A LINE
EXTENDING FROM 6 MILES EAST OF HARRISON TO 5 MILES SOUTHWEST OF
ST. JOHN...AND MOVING EAST AT 35 TO 40 MPH. THIS LINE WILL MOVE
QUICKLY INTO THE CENTRAL IDAHO PANHANDLE. HEAVY DOWNPOURS WILL
LIKELY CAUSE PONDING OF WATER GIVEN THE RECENT HEAVY RAINS.
WIND GUSTS UP TO 55 MPH ARE EXPECTED WITH THIS NARROW LINE OF
STORMS.
LOCATIONS IMPACTED INCLUDE...
PLUMMER...OAKESDALE...PINEHURST...ST. MARIES...WARDNER...
KELLOGG...SMELTERVILLE...OSBURN...WALLACE...MULLAN...CALDER.
LAT...LON 4695 11591 4697 11782 4759 11646 4753 11569
4750 11569 4747 11562 4745 11565 4744 11573
4736 11555 4730 11550 4726 11533
TIME...MOT...LOC 0800Z 271DEG 39KT 4747 11663 4705 11765The Spokane radar (KOTX), 88 km away, was scanning. The volume nearest the first event began at 08:27 UTC.
2 thunderstorm wind. Local standard time, as filed.
The St Maries COOP reported a tree had fallen onto power-lines in the Benewah Valley due to strong wind gusts associated with thunderstorms between 1230 AM PST and 100AM PST.
Strong wind gusts knocked down at least four large trees in the town of Osburn, Idaho. The toppled trees caused extensive damage to a motor home, car, storage shed, car port, and patio cover. One tree clipped a house resulting in minor damage. Two roofs were completely blown off from primary residences and several other roofs were damaged. Several power poles and power-lines were damaged. The Nuckols RAWS, located at 4000 feet just outside the town of Osburn, measured sustained winds of 31 mph with gusts to 60 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2011Every state in 2011This day in weather historyWarnings in Idaho, December 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 2026-09-24. Each event’s entry at NCEI: 353251, 353252.