Idaho, 2024

Flash Flood in Idaho, June 30, 2024

June 30, 2024 · NWS MSO · 1 event in 1 county or zone

Flooding occurred along the Salmon River Road as brief but intense rainfall occurred.

Where it happened

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  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$250,000
Crop damage
None recorded
Events
1

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.

What happened

The episode as NWS MSO wrote it up.

Flooding occurred along the Salmon River Road as brief but intense rainfall occurred.

What forecasters said that day

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 Jun 30, 12:46 PM MST, 2 hours 39 minutes earlier.

Area forecast discussion, Jun 30, 12:46 PM MST, 2 hours 39 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
146 PM MDT Sun Jun 30 2024

...5 PERCENT PROBABILITY OF SEVERE WIND AND HAIL ACROSS SOUTHWEST
MONTANA...LEMHI COUNTY IDAHO THROUGH THIS EVENING...

.DISCUSSION...

The biggest weather impact in the near term will be occurrence of
thunderstorms across the Northern Rockies throughout the remainder
of today. Southwest Montana and Lemhi County Idaho have a 5 percent
probability of damaging hail (greater than 1 inch diameter) and
damaging wind (60 mph or greater) through sunset this evening.

Otherwise through Independence Day, cool, showery, and breezy
conditions will remain in place across the Northern Rockies. Daytime
temperatures will be running generally 5-10 degrees below the
seasonal average through Thursday.

The next most significant weather impact is anticipated Friday
through the weekend, when 60-70 percent of weather models and their
ensembles suggest a very warm ridge of high pressure moving over the
Northern Rockies. Population centers across the region are projected
to warm 10-20 degrees above the seasonal average (90-105F). Now
would be a good time to ensure that you have a reliable way to avoid
or mitigate the heat. Water, shade, and air circulation are crucial
for avoiding adverse health effects from heat.

&&

.AVIATION...Thunderstorms will be present across the Northern
Rockies air space through 01/0600Z. There is a roughly 50 percent
probability of lightning across northwest/southwest Montana and
over Lemhi County in central Idaho during this time. Also, there
is a 5 percent probability of large hail and thunderstorm wind
gusts exceeding 50 knots for southwest Montana and Lemhi County
Idaho (including KBTM and KSMN). Terrain obscurations from low
ceilings will be common during this time as well. Ceilings will
steadily rise and obscurations lessen significantly after
01/0600Z.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

The radar

The Missoula radar (KMSX), 197 km away, was scanning. The volume nearest the first event began at 22:26 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Lemhi

When
June 30, 3:25 PM MST to 5:00 PM MST
Where
Lemhi County, 12.98 mi WSW of Shoup to 13.03 mi WSW of Shoup
Cause
Heavy Rain
Property damage
$250,000
Reported by
Department of Highways
Coordinates
45.310, -114.518

Flash flooding and mudslides occurred along Salmon River Road from just above Ebenezer Campground to just below Owl Creek. Radar estimates of up to 1.25 inches of rain fell over a half hour period across the southern half of the Owl Creek Basin. There were three major slides along the Salmon River Road, near Poverty Flat, Skull Gulch, and one roughly 0.3 miles in length where the road bank collapsed into the river. The Skull Gulch slide destroyed at least one outbuilding. There were also 30 to 50 additional small slides across the Salmon River Road that didn't cause structural damage.

What these are

Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Idaho in 2024Every state in 2024This day in weather historyWarnings in Idaho, June 2024

Sources

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: 1178603.