Thunderstorm winds blew down a large sign at Simplot in St Anthony. The same storm also blew over a fuel shed on the south side of town near Simplot.
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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 PIH wrote it up.
Thunderstorm winds blew down a large sign at Simplot in St Anthony. The same storm also blew over a fuel shed on the south side of town near Simplot.
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 Apr 21, 1:29 PM MST, 2 hours 21 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 229 PM MDT WED APR 21 2010 .SHORT TERM...TODAY THROUGH FRIDAY NIGHT. LARGE UPPER LEVEL LOW CONTINUES TO SLOWLY EDGE EASTWARD ACROSS SOUTHERN NEVADA. MOISTURE IS PUMPING NORTHWARD ACROSS THE AREA TRIGGERING NUMEROUS RAIN SHOWERS AND THUNDERSTORMS THIS AFTERNOON. THE BULK OF THE ACTIVITY HAS BEEN ALONG THE EASTERN HALF OF THE FORECAST AREA. CLEARING BEHIND THE FIRST WAVE OF THUNDERSTORMS HAS ALLOWED THE ATMOSPHERE TO REALLY DESTABILIZE WITH A SECOND ROUND MOVING THROUGH THE SOUTH-CENTRAL HIGHLANDS AND MORE THUNDERSTORMS TRACKING THIS WAY FROM NORTHERN UTAH. STORMS MAY HAVE SMALL HAIL AND WIND GUSTS TO 50 MPH AND HEAVY DOWNPOURS. EXPECT THUNDERSTORM ACTIVITY TO FILL IN EASTWARD ACROSS THE REST OF THE FORECAST AREA LATER TODAY. ISOLATED SEVERE THUNDERSTORMS ARE NOT OUT OF THE QUESTION AND HAVE BEEN OCCURRING IN NORTHERN UTAH THIS AFTERNOON. LOW DRIFTS EASTWARD INTO THE FOUR CORNERS AREA BY THURSDAY AFTERNOON. BANDS OF SHOWERS WILL CONTINUE TO ROTATE ACROSS THE AREA TONIGHT AND THURSDAY. BY LATE THURSDAY NIGHT IT ARRIVES NI THE EASTERN GREAT PLAINS...WHICH WILL SHIFT THE BAND OF PRECIPITATION PRIMARILY ACROSS THE EASTERN AND SOUTHERN HIGHLANDS. SHOWERS TAPER OFF FRIDAY AND A RIDGE DRIES OUT THE FORECAST AREA FRIDAY NIGHT. SNOW LEVELS ARE EXPECTED TO REMAIN RATHER HIGH DURING THE TIME FRAME. EXPECT THEM TO REMAIN ABOVE 9000 FEET THROUGH TONIGHT AND THEN SLOWLY LOWER TO 6000 FEET BY FRIDAY. OVERALL...SNOW AMOUNTS WILL BE PRIMARILY LIMITED TO ALL BUT THE HIGHEST PEAKS. .LONG TERM...SATURDAY THROUGH NEXT WEDNESDAY. THE GFS AND ECMWF MODELS ARE BRINGING IN A SHORT WAVE DOWN FROM BRITISH COLUMBIA SATURDAY NIGHT INTO SUNDAY IMPACTING MOSTLY THE NORTHERN CENTRAL MOUNTAINS AND AREAS ALONG THE MONTANA/IDAHO DIVIDE. FROM HERE THE MODELS DIFFER SLIGHTLY IN INTENSITY AND TIMING BUT HAVE COME MORE IN LINE THAN THE PREVIOUS RUN. THEY BOTH BRING RIDGING IN SUNDAY NIGHT INTO MONDAY. THEN THEY BRING IN A BROAD UPPER LEVEL LOW TUESDAY NIGHT THROUGH THURSDAY OVER SOUTHERN IDAHO. EXPECT BELOW NORMAL TEMPERATURES THROUGHOUT THE PERIOD AND WIDESPREAD PRECIPITATION MAINLY AT THE END OF THE PERIOD. WYATT && .AVIATION...UPPER-LEVEL LOW OVER SOUTHERN NEVADA IS CURRENTLY SPINNING OFF SHORT WAVES WITH AMPLE MOISTURE OVER OUR AREA. EXPECT ISOLATED TO SCATTERED THUNDERSTORMS AND RAIN SHOWERS THROUGH THE AFTERNOON BECOMING WIDESPREAD RAIN SHOWERS OVERNIGHT THROUGH TOMORROW. WILL SEE MVFR CONDITIONS DURING SHOWERS THIS AFTERNOON OTHERWISE EXPECT VFR CONDITIONS UNTIL THIS EVENING. ALL TAF SITES WILL LIKELY SEE MVFR CONDITIONS THIS EVENING LASTING THROUGH TOMORROW NIGHT. EXPECT POSSIBLE IFR CONDITIONS AT TAF SITES ACROSS THE SNAKE RIVER PLAIN DURING HEAVIER SHOWERS TONIGHT. WYATT && .PIH WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 10 PM MDT THIS AFTERNOON IDZ031. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE POCATELLO ID 500 AM MDT WED APR 21 2010 IDZ017>025-031-032-221300- EASTERN MAGIC VALLEY-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- 500 AM MDT WED APR 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN IDAHO. .DAY ONE...TODAY AND TONIGHT EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TODAY. SNOW LEVELS 8000 FEET TO 9000 FEET. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY VALLEY RAIN AND HIGH MOUNTAIN SNOW ON THURSDAY. SNOW LEVELS OF 7000 FEET. DRIER WEATHER MOVING IN FRIDAY. .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.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE POCATELLO
359 PM MDT WED APR 21 2010
IDZ022>025-212245-
CARIBOU ID-ONEIDA ID-POWER ID-BANNOCK ID-FRANKLIN ID-
359 PM MDT WED APR 21 2010
THE NATIONAL WEATHER SERVICE IN POCATELLO HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
WESTERN FRANKLIN COUNTY IN SOUTHEAST IDAHO
BANNOCK COUNTY IN SOUTHEAST IDAHO
EAST CENTRAL POWER COUNTY IN SOUTHEAST IDAHO
EASTERN ONEIDA COUNTY IN SOUTHEAST IDAHO
SOUTHWESTERN CARIBOU COUNTY IN SOUTHEAST IDAHO
UNTIL 445 PM MDT
AT 356 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 7 MILES NORTHEAST OF CHERRY CREEK..MOVING NORTH
AT 60 MPH.
HAIL UP TO ONE-HALF INCH IN DIAMETER WITH SOME MINOR
ACCUMULATIONS... WIND GUSTS UP TO 50 MPH AND HEAVY RAIN ARE EXPECTED
WITH THIS STORM.
LOCATIONS IMPACTED INCLUDE...
SWANLAKE...
DOWNEY...
VIRGINIA...
ARIMO...
LAVA HOT SPRINGS...
MCCAMMON...
PEBBLE...
INKOM...
THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
LAT...LON 4200 11231 4274 11269 4286 11186 4242 11185
4229 11183 4225 11184 4199 11183 4200 11206
4199 11207 4200 11229
TIME...MOT...LOC 2157Z 174DEG 54KT 4216 11211
JKEYESPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE POCATELLO
411 PM MDT WED APR 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0409 PM HAIL PRESTON 42.10N 111.87W
04/21/2010 M0.25 INCH FRANKLIN ID CO-OP OBSERVER
SMALL TO PEA-SIZE HAIL OCCURRED AT THE HIGH SCHOOL.
&&
GWICKLUNPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE POCATELLO
412 PM MDT WED APR 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0411 PM HAIL SE PRESTON 42.10N 111.87W
04/21/2010 E0.25 INCH FRANKLIN ID TRAINED SPOTTER
1/4 HAIL WITH BRIEF HEAVY RAIN
&&
TWYATTSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE POCATELLO 425 PM MDT WED APR 21 2010 IDZ019-020-032-212315- CLARK ID-JEFFERSON ID-BUTTE ID- 425 PM MDT WED APR 21 2010 THE NATIONAL WEATHER SERVICE IN POCATELLO HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR... EAST CENTRAL BUTTE COUNTY IN EAST CENTRAL IDAHO EXTREME SOUTHWESTERN CLARK COUNTY IN EASTERN IDAHO WEST CENTRAL JEFFERSON COUNTY IN SOUTHEAST IDAHO UNTIL 515 PM MDT AT 421 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 8 MILES SOUTH OF NORTHWEST INL..MOVING NORTHWEST AT 25 MPH. WIND GUSTS UP TO 45 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN. LOCATIONS IMPACTED INCLUDE... NORTHWEST INL... LAT...LON 4393 11305 4403 11275 4376 11250 4364 11275 TIME...MOT...LOC 2225Z 145DEG 20KT 4376 11271
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE POCATELLO
441 PM MDT WED APR 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0440 PM HAIL 1 SW POCATELLO 42.87N 112.48W
04/21/2010 E0.50 INCH BANNOCK ID TRAINED SPOTTER
1/2 HAIL AND HEAVY RAIN
&&
TWYATTSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE POCATELLO
442 PM MDT WED APR 21 2010
IDZ020-021-212330-
BUTTE ID-BINGHAM ID-POWER ID-BANNOCK ID-
442 PM MDT WED APR 21 2010
THE NATIONAL WEATHER SERVICE IN POCATELLO HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
EXTREME SOUTH CENTRAL BUTTE COUNTY IN EAST CENTRAL IDAHO
NORTHWESTERN BANNOCK COUNTY IN SOUTHEAST IDAHO
NORTHEASTERN POWER COUNTY IN SOUTHEAST IDAHO
WESTERN BINGHAM COUNTY IN SOUTHEAST IDAHO
UNTIL 530 PM MDT
AT 436 PM MDT...STORM SPOTTERS REPORTED A STRONG THUNDERSTORM NEAR
THE POCATELLO AIRPORT..MOVING NORTHWEST AT 30 MPH.
HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS IN EXCESS OF 40
MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN. A TRAINED
SPOTTER REPORTED VERY HEAVY RAIN AND MARBLE SIZE HAIL NEAR THE FAR
WEST SIDE OF POCATELLO AS THE STORM PASSED.
LOCATIONS IMPACTED INCLUDE...
SPRINGFIELD AND PINGREE...
THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
LAT...LON 4317 11300 4327 11300 4339 11277 4291 11238
4282 11256
TIME...MOT...LOC 2241Z 143DEG 27KT 4293 11256
JKEYESThe Pocatello radar (KSFX), 126 km away, was scanning. The volume nearest the first event began at 22:51 UTC.
1 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds blew down a large sign at Simplot in St Anthony. The same storm also blew over a fuel shed on the south side of town near Simplot.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2010Every state in 2010This day in weather historyWarnings in Idaho, April 2010
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: 225314.