A funnel cloud was photographed in Idaho Falls and accumulating small hail caused multiple accidents on interstate 15 near Fort Hall.
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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.
A funnel cloud was photographed in Idaho Falls and accumulating small hail caused multiple accidents on interstate 15 near Fort Hall.
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 May 18, 1:51 AM MST, 9 hours 54 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 251 AM MDT MON MAY 18 2015 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT. A RELATIVELY QUIET MORNING SO FAR EXCEPT ACROSS THE FAR WESTERN EDGE OF OUR FORECAST AREA. A LINE OF SHOWERS IS LIFTING NORTH-NORTHWEST THROUGH THE MOUNTAINS NEAR BURLEY AND THE WESTERN MAGIC VALLEY. OTHERWISE...SOME CLOUDS ARE SLOWLY LIFTING ACROSS THE STATE. AS THE LOW CREEPS NORTHEAST TOWARD THE SIERRAS...MOISTURE WILL CONTINUE TO SPREAD NORTHWARD. THIS WILL SET THE STAGE FOR SHOWERS THIS AFTERNOON AND EVENING...WITH ISOLATED THUNDERSTORMS. WE WILL LIKELY SEE SMALL HAIL AND POCKETS OF HEAVY RAINFALL WITH STRONGER BANDS AND CELLS. THE LOW PICKS UP A LITTLE SPEED AND REACHES WYOMING BY TOMORROW EVENING. THERE ARE SOME SUBTLE DIFFERENCES IN THE MODELS THIS MORNING WITH THE EXACT TRACK...WHICH ARE ACTUALLY LEADING TO BIGGER ISSUES WITH WHERE AND HOW MUCH RAINFALL OUR SIDE OF THE STATE WILL GET. THE NAM IS PRETTY SPARSE WITH SHOWERS OVERNIGHT/TUESDAY MORNING AND PUTS ANY FOCUS ALONG THE MONTANA AND WYOMING BORDERS. THE GFS AND THE ECMWF KEEP THE FOCUS FARTHER SOUTH...GENERALLY SOUTH OF A STANLEY-INL-DRIGGS LINE. WE TRENDED TOWARD THE GFS/ECMWF IDEA BUT BLENDED IN SOME SLIGHTLY HIGHER CHANCES FARTHER NORTH. A SIMILAR TREND IN PLACING HEAVIER PRECIPITATION IS REFLECTED IN THE FORECAST FOR TOMORROW AFTERNOON. HOWEVER...WITH THE LOW GETTING CLOSER EXPECT HIGHER CHANCES ACROSS THE BOARD. HEAVIER RAIN IS POSSIBLE ONCE AGAIN...WITH ANY HAIL POTENTIAL DETERMINED ON IF WE GET UNSTABLE ENOUGH FOR STORMS. WE WILL GRADUALLY SEE SHOWERS THIN OUT TOMORROW NIGHT AS THE STORMS PULLS AWAY...WITH WRAPAROUND LIKELY FOCUS ACROSS THE SOUTHERN AND EASTERN MOUNTAINS. TEMPERATURES WILL REMAIN MILD AT NIGHT DUE TO THE COMBINATION OF CLOUDS AND MOISTURE IN THE AIR. HIGHS WILL REMAIN CLOSE TO OR JUST BELOW AVERAGE FOR THE END OF MAY. KEYES .LONG TERM...WEDNESDAY THROUGH MEMORIAL DAY. IF YOU WERE LOOKING FOR DRY WEATHER HEADING INTO THE HOLIDAY WEEKEND...SORRY TO SAY THAT LIKELY WON'T BE THE CASE. IF YOU WERE WISHING FOR MORE MOISTURE...THINGS WILL BE RIGHT UP YOUR ALLEY. THE NEXT LOW MOVES INLAND FOR THE MIDDLE AND END OF THE WEEK. THE TRACK INITIALLY LOOKS TO BE A BIT FARTHER SOUTH BUT IT STILL LOOKS LIKE PLENTY OF MOISTURE STREAMS NORTH INTO IDAHO. THAT LOW MOVES INTO THE HIGH PLAINS BY SATURDAY...BUT ANOTHER LOW IS RIGHT ON ITS HEELS. INTERESTINGLY ENOUGH...THIS ONE IS DROPPING IN FROM THE NORTH. IT THE CURRENT TREND IS TO DROP IT SOUTH SOMEWHERE OVER WASHINGTON...OREGON OR WESTERN IDAHO DEPENDING ON WHICH MODEL YOU CHOOSE. THE POSITION OF THE LOW WILL DETERMINE IF AND WHEN WE MIGHT SEE ANY BREAKS SUNDAY AND MONDAY. FOR NOW...WE WENT WITH A RATHER BROAD APPROACH AND GAVE EVERYONE A CHANCE OF RAIN/HIGH PEAK SNOW FOR NOW. TEMPERATURE TRENDS WILL REMAIN THE SAME...WITH MILD NIGHTS AND AFTERNOON HIGHS CLOSE TO AVERAGE. KEYES && .AVIATION...AN UPPER LOW MOVING FROM THE CA COAST TO THE GREAT BASIN BY TUE WILL RESULT IN SCT SHOWERS/ISOLD AFTN AND EVE TSTMS. VFR CONDITIONS ARE EXPECTED TO PREVAIL THRU TONIGHT. HEDGES && .FIRE WEATHER...AN UPPER LOW MOVING FROM THE CALIFORNIA COAST TO THE GREAT BASIN BY TUESDAY WILL RESULT IN SCATTERED SHOWERS AND ISOLATED AFTERNOON/EVENING THUNDERSTORMS THROUGH MIDWEEK. AFTERNOON HUMIDITY READINGS WILL REMAIN RELATIVELY HIGH DUE TO THE CURRENT AND PAST PRECIPITATION. SHOWERS AND AFTERNOON THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH THE END OF THE WEEK. HEDGES && .HYDROLOGY...SOME AREAS HAVE RECEIVED SEVERAL INCHES OF RAIN OVER THE PAST FEW DAYS. THAT HAS LEAD TO RISING WATER LEVELS ON AREA STREAMS AND EVEN A FEW OF THE MAIN RIVERS. HOWEVER...WIDESPREAD FLOODING HASN'T BEEN SEEN. WITH MORE RAIN/HIGH ELEVATION SNOW ON THE WAY...WE CAN EXPECT MORE OF THE SAME. RIGHT NOW...WE ARE EXPECTING ANY MAJOR OR WIDESPREAD FLOODING BUT MORE LOCALIZED ISSUES ARE CERTAINLY POSSIBLE. ANOTHER THING TO BE ON THE LOOKOUT FOR IS RUNOFF AND ROCK- OR MUDSLIDES IN THE TERRAIN AREAS. THIS TYPE OF PATTERN IS CONDUCIVE TO LOOSENING ROCK. KEYES && .PIH WATCHES/WARNINGS/ADVISORIES... NONE. &&
The national radar mosaic for the moment the first event began.
1 funnel cloud, 1 hail. Local standard time, as filed.
Funnel cloud photographed on the south side of Idaho Falls around 1 pm MDT.
Small hail began accumulating on interstate 15 in Fort Hall and many cars slid off the interstate into ditches and the median with one collision occurring. One individual received minor injuries and was transported to a hospital.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2015Every state in 2015This day in weather historyWarnings in Idaho, May 2015
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: 581762, 581840.