A weak Canadian storm system combined with an unstable but very dry airmass allowed the formation of a severe thunderstorm in Lemhi County. The very dry nature of the airmass allowed winds to accelerate to 64 mph in Salmon even though the storm appeared fairly weak on radar.
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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 MSO wrote it up.
A weak Canadian storm system combined with an unstable but very dry airmass allowed the formation of a severe thunderstorm in Lemhi County. The very dry nature of the airmass allowed winds to accelerate to 64 mph in Salmon even though the storm appeared fairly weak on radar. Many tree branches were knocked down and some roof and chimney damage was reported.
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 Missoula, MT wrote its last area forecast discussion before the first event at Jul 13, 3:18 PM MST, 4 hours 57 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 418 PM MDT TUE JUL 13 2010 .UPDATE...CANCELED THE LAKE WIND ADVISORY && .DISCUSSION...THE WINDS HAVE STARTED TO SUBSIDE SOME ACROSS FLATHEAD LAKE WHICH HAS FALLEN BELOW LAKE WINDS ADVISORY CRITERIA. THE LAKE IS STILL EXPECTED TO SEE SOME GUSTY WINDS THROUGH THE EVENING. && && .PREV DISCUSSION... /ISSUED 309 PM MDT TUE JUL 13 2010/ DISCUSSION... TONIGHT THROUGH THURSDAY...BREEZY CONDITIONS WILL CONTINUE ACROSS THE NORTHERN ROCKIES THROUGH THIS EVENING...AS A RELATIVELY MOISTURE STARVED STORM SYSTEM OVER SOUTHWEST CANADA MOVES EAST OF THE CONTINENTAL DIVIDE. HOWEVER...AS THE TRAILING OF THIS SYSTEM GRAZES THE CANADIAN BORDER TONIGHT...A SLIGHT CHANCE OF PRECIPITATION WILL EXIST THROUGH EARLY WEDNESDAY ACROSS NORTHWEST MONTANA. BY MIDDAY WEDNESDAY...HIGH PRESSURE WILL BE SLOWLY STRENGTHEN OVER THE PACIFIC NORTHWEST. THIS DEVELOPING HIGH PRESSURE WILL ALLOW SKIES TO CLEAR AND AFTERNOON TEMPERATURES TO WARM BACK TO NEAR AND ABOVE SEASONAL AVERAGES BY THURSDAY. THURSDAY NIGHT THROUGH MONDAY...A MOIST SOUTHWEST FLOW SETS UP THURSDAY NIGHT INTO FRIDAY AND COULD BRING ENOUGH MOISTURE ALONG WITH AN UNSTABLE ATMOSPHERE TO PRODUCE SOME SHOWERS OR THUNDERSTORMS. WARM AND DRY SEASONAL CONDITIONS WILL ALSO CONTINUE THROUGH THE END OF THE WEEK. A WEAK DISTURBANCE IS POSSIBLE OVER THE WEEKEND THAT COULD BRING TEMPERATURES DOWN A FEW DEGREES. AVIATION...SURFACE WINDS GUSTING TO 30 KNOTS FROM THE WEST AND SOUTHWEST WILL EXIST ACROSS THE NORTHERN ROCKIES THROUGH 14/0600Z. THEREAFTER...WINDS ARE EXPECTED TO WEAKEN SIGNIFICANTLY. SOME LOWER CEILINGS MAY EXIST NORTH OF KGPI THROUGH 14/1500Z...WITH ISOLATED RAIN SHOWERS PRESENT. FEW WEATHER RELATED AVIATION IMPACTS ARE ANTICIPATED TO EXIST AFTER 14/1500Z. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...NONE. ID...NONE. && SHORT TERM...SMITH PREVIOUS DISCUSSION....ZUMPFE/KOLATA AVIATION...ZUMPFE
The Missoula radar (KMSX), 207 km away, was scanning. The volume nearest the first event began at 03:13 UTC.
2 thunderstorm wind. Local standard time, as filed.
Strong winds blew the chimney off of the Syringa Lodge as well as some of the tin on the roof.
A 64 mph wind gust was measured by the salmon RAWS station.
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, July 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: 252752, 252753.