A fast moving Pacific storm system dropped 10 to 20 inches of snow at several SNOTEL sites. Trained spotters reported 6 to 9 inches in the Hailey and Bellevue areas.
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 PIH wrote it up.
A fast moving Pacific storm system dropped 10 to 20 inches of snow at several SNOTEL sites. Trained spotters reported 6 to 9 inches in the Hailey and Bellevue areas.
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 Pocatello, ID wrote its last area forecast discussion before the first event at Dec 16, 2:28 PM MST, 8 hours 32 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 228 PM MST SUN DEC 16 2012 .SHORT TERM...TONIGHT THROUGH WED NIGHT. A MAJOR STORM IS MOVING THROUGH THE PACIFIC NORTHWEST AT THIS TIME...INCLUDING AREAS OF BLIZZARD CONDITIONS. THIS SAME STORM WILL BE ON TOP OF CENTRAL AND EASTERN IDAHO LATE TONIGHT. IT IS ALL POWERED BY A 160KT-PLUS JET STREAK AND SOME FAIRLY DECENT MOISTURE. THE MAIN FORECAST PROBLEM WILL BE WIND...WITH THE SNOW FALL AMOUNT A CLOSE SECOND. THE COLD FRONT PASSAGE OCCURS IN THE LATE MORNING/EARLY AFTERNOON FOR THE HEAVILY POPULATED AREAS OF THE FORECAST AREA. THIS WILL MEAN A WIND SWITCH THAT WILL UNLEASH THE STRONGEST WIND. THE LOCAL STUDY ON WINDS PRODUCED A SCORE IN THE UPPER 80S FOR 17/18Z AND 18/00Z...WHICH MEANS CONFIDENT HIGH WIND WARNING. ALL THE MAIN FACTORS FOR THIS STUDY ARE SCORING HIGH...THE PREVIOUSLY MENTIONED JET STREAK...WESTERLY RATHER THAN SOUTHWESTERLY UPPER LEVEL FLOW...MODERATE COLD AIR ADVECTION FOR MIXING...AND 700MB WIND THAT IS NEARLY OFF THE CHART...ESPECIALLY MON MORNING...OF 45KT TO 63KT OVER THE SNAKE RIVER PLAIN...AND SLP PRESSURE GRADIENTS STAYING ABOVE 6MB ACROSS SOUTHERN IDAHO. THIS STUDY WAS EVALUATED USING THE WEAKER SCENARIO OF THE NAM. THE GFS HAD A STRONGER SOLUTION...AS EVIDENCED BY THE STRONGER MOS GUIDANCE WIND. THUS ISSUED A HIGH WIND WARNING FOR THE THREE VALLEY ZONES. PRECIPITATION AMOUNTS HAVE NOT CHANGED MUCH SO THE WINTER WEATHER HIGHLIGHTS WILL ALSO BE CONTINUED. BEYOND MON NIGHT...THE WESTERLY FLOW WILL CONTINUE TO PRODUCE CLOUDS AND PRECIPITATION MAINLY IN THE MOUNTAINS ON THE OROGRAPHICALLY ENHANCED SIDES...THUS STANLEY AND CHALLIS ARE MORE UNDER THE THREAT THAN THE WOOD RIVER BASIN...AND THEN THE ID-WY BORDER MOUNTAINS DOWN TO THE BEAR LAKE BASIN. AMOUNTS...IF ANY...WILL BE LIGHT HOWEVER. DO NOT SEE A RETURN OF ANY SERIOUS WIND LIKE MONDAY. MESSICK .LONG TERM...THURSDAY THROUGH SUNDAY. EASTERN IDAHO UNDER TRANSITION FROM PASSAGE OF UPPER TROUGH INTO RIDGE CONDITIONS WEDNESDAY INTO THURSDAY. MODELS IN GOOD AGREEMENT OF SYNOPTIC FEATURES ESPECIALLY WITH STRENGTH AND TIMING OF RIDGE DEVELOPMENT. GFS HOLDS ON TO A BIT MORE MOISTURE THAN THE ECMWF DURING THIS TRANSITION PERIOD LEAVING POTENTIAL FOR WEAK POPS OVER HIGHER ELEVATION AREAS. THURSDAY APPEARS TO BE DRIEST OF PERIOD EVEN WITH MORE UNSETTLED GFS. MODEL SOLUTIONS BEGIN TO DIVERGE THROUGH REMAINDER OF FORECAST PERIOD AS DEEP PACIFIC TROUGH SHIFTS CLOSER TO COAST. BOTH ECMWF AND GFS PUSH PRECIP ACROSS THE REGION EACH PERIOD THOUGH GFS REMAINS THE WETTER MODEL. MADE NO CHANGE TO GOING POPS PAST FRIDAY GIVEN UNCERTAINTY IN DETAILS WITH GOING FORECAST REMAINING AT OR ABOVE CLIMO AT THIS TIME. GUIDANCE THROUGH THE PERIOD WARMED SLIGHTLY SO BLENDED TEMPS UPWARD. MODELS CONTINUE TO SHOW THE TROUGH MOVING INLAND NEXT SUNDAY INTO TUESDAY WHICH WOULD PRODUCE DIFFICULT HOLIDAY TRAVEL CONDITIONS AND A WHITE CHRISTMAS. PRESTON / DHM && .AVIATION...A MAJOR WINTER STORM WILL BE MOVING THROUGH THE AREA TONIGHT THROUGH TUESDAY MORNING. OVERNIGHT EXPECT SNOW TO START FROM WEST TO EAST WITH IFR CONDITIONS AT ALL AIRPORTS BY TOMORROW MORNING. BASED ON THE CURRENT MOISTURE TRENDS LOOKS LIKE LIFR FROM 10Z THROUGH 18Z DUE TO CEILINGS AND VISIBILITY FROM THE SNOW. DUE TO THE STRENGTH OF THE SYSTEM...STRONG WESTERLY WINDS ARE POSSIBLE IN THE SNAKE RIVER PLAIN AT SPEEDS GREATER THAN 40 TO 50 KTS ALONG WITH WINDSHEAR ABOVE THE SURFACE. THE BAD CONDITIONS ARE EXPECTED TO REMAIN THROUGH MONDAY AFTERNOON AND SLOWLY INCREASE TO IFR AND MVFR BY TUESDAY MORNING. PRESTON && .PIH WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 3 AM TO 11 PM MST MONDAY IDZ017-020-021. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 5 AM MST TUESDAY IDZ020-021. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 5 AM MST TUESDAY BELOW 7000 FEET FOR THE IDZ018-019-023-025-031. WINTER STORM WARNING FROM 11 PM THIS EVENING TO 5 AM MST TUESDAY ABOVE 7000 FEET FOR THE IDZ018-019-023-025-031. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 5 AM MST TUESDAY IDZ022-024. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 5 AM MST TUESDAY IDZ032. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE POCATELLO ID 504 AM MST SUN DEC 16 2012 IDZ017-171215- EASTERN MAGIC VALLEY- 504 AM MST SUN DEC 16 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN IDAHO. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY WINDS WILL BECOME GUSTY TOMORROW OVER THE AREA WITH PEAK GUSTS OF 30 TO 35 MPH. LIGHT SNOWFALL IS ALSO EXPECTED. .SPOTTER INFORMATION STATEMENT... WE ASK TRAINED SPOTTERS AND CITIZENS TO REPORT SIGNIFICANT WEATHER CONDITIONS WHEN IT IS SAFE TO DO SO. THESE CONDITIONS MAY INCLUDE HAIL...TORNADOES...STRONG WIND...DUST STORMS...SNOWFALL... EXTREME COLD TEMPERATURES...FREEZING RAIN OR HEAVY RAIN...DENSE FOG...AND FLOODING OR ICE JAMS. INFORMATION ABOUT THESE HAZARDOUS CONDITIONS SHOULD BE CALLED INTO YOUR NATIONAL WEATHER SERVICE OFFICE IN POCATELLO USING THE 1-800 SEVERE WEATHER HOTLINE...OR 208-233-0834. IDZ018>025-031-032-171215- SAWTOOTH MOUNTAINS-UPPER SNAKE HIGHLANDS-UPPER SNAKE RIVER PLAIN- LOWER SNAKE RIVER PLAIN-SOUTH CENTRAL HIGHLANDS-CARIBOU HIGHLANDS- CACHE VALLEY/IDAHO PORTION-WASATCH MOUNTAINS/IDAHO PORTION- BIG AND LITTLE WOOD RIVER REGION-LOST RIVER/PAHSIMEROI- 504 AM MST SUN DEC 16 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN IDAHO. .DAY ONE...TODAY AND TONIGHT SNOW WILL CONTINUE OVER THE AREA AND INTENSIFY THIS AFTERNOON OVER THE EASTERN HIGHLANDS. HEAVIER SNOW IS EXPECTED TO FALL OVERNIGHT AS WINDS INCREASE AS WELL. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY SIGNIFICANT SNOWFALL WITH GUSTY WINDS IS EXPECTED MOST OF MONDAY AND MAY IMPACT EARLY HOLIDAY TRAVEL. BLOWING AND DRIFTING SNOW MAY REDUCE VISIBILITY FOR MUCH OF THE DAY. ACCUMULATING SNOW MAY TEMPORARILY CLOSE ROADS. .SPOTTER INFORMATION STATEMENT... WE ASK TRAINED SPOTTERS AND CITIZENS TO REPORT SIGNIFICANT WEATHER CONDITIONS WHEN IT IS SAFE TO DO SO. THESE CONDITIONS MAY INCLUDE HAIL...TORNADOES...STRONG WIND...DUST STORMS...SNOWFALL... EXTREME COLD TEMPERATURES...FREEZING RAIN OR HEAVY RAIN...DENSE FOG...AND FLOODING OR ICE JAMS. INFORMATION ABOUT THESE HAZARDOUS CONDITIONS SHOULD BE CALLED INTO YOUR NATIONAL WEATHER SERVICE OFFICE IN POCATELLO USING THE 1-800 SEVERE WEATHER HOTLINE...OR 208-233-0834.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE POCATELLO
747 PM MST SUN DEC 16 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0745 PM SNOW VICTOR 43.60N 111.11W
12/16/2012 M5.0 INCH TETON ID TRAINED SPOTTER
5 INCHES OF SNOW FELL SINCE 8 AM LOCAL TIME.
&&
EJPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE POCATELLO
753 PM MST SUN DEC 16 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0745 PM SNOW ISLAND PARK 44.42N 111.37W
12/16/2012 E9.0 INCH FREMONT ID TRAINED SPOTTER
ESTIMATES 8 INCHES OVERNIGHT WITH 1 ADDITIONAL INCH
DURING THE DAY TODAY.
&&
EJP4 heavy snow. Local standard time, as filed.
SNOTEL sites reporting heavy snow were: Smiley Mountain with 11 inches, Mill Creek Summit with 11 inches, and Bear Canyon with 12 inches.
The White Elephant SNOTEL site reported 18 inches of snow.
The Sedgwick Peak SNOTEL site recorded 10 inches of snow.
Trinaed spotters reported 8 inches of snow in Bellevue and 9 inches in Hailey. SNOTEL snow amounts were: 13 inches at Swede Peak, 14 inches at Lost Wood Divide, 12 inches at Hyndman, 12 inches at Galena Summit, 13 inches at Galena, 11 inches at Garfield Ranger Station, and 12 inches at Chocolate Gulch.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2012Every state in 2012This day in weather historyWarnings in Idaho, December 2012
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: 425156, 425157, 425158, 425160.