Flooding in Idaho, March 13 to 31, 2018

Name: Flooding in Idaho, March 13 to 31, 2018
Start: 2018-03-13T05:00
End: 2018-03-31T23:00
Location: Idaho

March 13 to 31, 2018 · NWS PIH · 7 events in 7 counties and zones

A return to heavy mountain snows in late February and early March added significantly to the snow pack especially in the Upper Snake River Highlands and snow melt and heavy rains occurred sporadically from the middle of the month onward. The worst of the flooding occurred in Clark and Madison which were both declared state disaster areas by the end of the month.

Where it happened

Every event with a place to put it. Tap one for its entry below.

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: $2.4 million
Crop damage: None recorded
Events: 7

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 PIH wrote it up.

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 Pocatello, ID wrote its last area forecast discussion before the first event at Mar 13, 1:36 AM MST, 3 hours 24 minutes earlier.

Area forecast discussion, Mar 13, 1:36 AM MST, 3 hours 24 minutes before

Area Forecast Discussion
National Weather Service Pocatello ID
236 AM MDT Tue Mar 13 2018

.SHORT TERM...Today through Thursday night. We remain under the
influence of upper ridging today and tonight. WV imagery shows
some energy is beginning to lift out of the Pacific trough, and is
beginning to make landfall. Ridging should shift eastward tonight,
allowing the shortwave to push into Idaho. Models show onset of
precipitation between 06Z and 12Z Wednesday for the Central
Mountains, and quickly overspreading the rest of the forecast area
after sunrise. Warm temperatures will keep snow levels fairly
high, but the higher Central Mountain peaks may see a quick 3 to 4
inches, and tapering off after 12Z. Weather will remain unsettled
while the initial Pacific wave rotates through the Great Basin
into UT/WY by Thursday night. Heaviest precip looks like it will
accompany the surface cold front, which should work its way
through southeast Idaho Wednesday afternoon. Convection may
develop along the cold front around this time, so kept thunder
mention. Hinsberger.

.LONG TERM...Friday through Tuesday. Overall forecast trends
remain similar to previous solution with models coming into better
agreement early in the period. Pacific low in place with main center
along CA/OR coastal border, and secondary shortwave/low wrapped
around East Idaho to low center in central Plains. East Idaho
between these two features but still under moist flow with difluence
aloft. So despite guidance/model solutions indicating lack of QPF
across the region, maintained some mention of showers most areas,
but mainly focused toward the southwest half in closer proximity to
main low. Second main shortwave generally associated with some
semblance of main trough axis, shifts across the region on
Saturday. This should be a fairly active period and have
maintained higher PoP most areas, shifting focus to along WY
border overnight into early Sunday. Model consensus degrades from
there. General idea is that low redevelops into the Pacific, but
this leaves much of East Idaho under the influence of weak
shortwaves trying to shift/meander through strengthening ridge
over the Great Basin. Hard to drop all precipitation under this
scenario, but overall trend should be drier than earlier in the
period, at least until next amplified low pushes inland later in
the week. DMH

&&

.AVIATION...So far this morning there is no sign of developing fog,
and surface dew point depressions are a little bit higher than
yesterday morning. Will likely leave BCFG around sunrise, but
confidence is quite low. Higher cloud cover trying to push into
ridge axis from the west, but conditions will remain VFR into
tonight most areas. Exception will be KSUN as band of precipitation
associated with next system begins to shift into the central
mountains after 06Z. Will likely see ceilings there drop to IFR with
-SHRASN after 09Z. This precip band is expected to shift toward the
remainder of the sites during the day Wed. DMH

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

7 flood. Local standard time, as filed.

Flood, Clark

When: March 13, 5:00 AM MST to March 31, 11:00 PM MST
Where: Clark County, 10 mi NW of Kilgore to 10 mi WNW of Spencer
Cause: Heavy Rain / Snow Melt
Property damage: $680,000
Reported by: Emergency Manager
Coordinates: 44.502, -112.023

Snow melt began in earnest with warmer temperatures combined with periods of heavy rain in the latter half of March. This caused extensive sheet flooding in Clark County to the extent that the governor declared it a state of Idaho disaster area. Several county roads received extensive damage and were washed away. 1 home in the Medicine Lodge area flooded completely along with hay bail damage and crop damage. The Birch Creek Campground also had extensive damage with several campgrounds along the birch Creek washed away. The county placed damage estimates close to 700 thousand dollars.

Flood, Butte

When: March 13, 10:00 AM MST to March 31, 11:00 PM MST
Where: Butte County, 20 mi NW of Howe to 10 mi W of Arco Butte
Cause: Heavy Rain / Snow Melt
Property damage: $75,000
Reported by: Emergency Manager
Coordinates: 43.985, -113.284

Extensive sheet flooding caused extensive damage to county roads.

Flood, Custer

When: March 13, 10:00 AM MST to March 31, 11:00 PM MST
Where: Custer County, 10 mi N of (U15)challis Arpt to 10 mi W of Stanley
Cause: Heavy Rain / Snow Melt
Property damage: $65,000
Reported by: Emergency Manager
Coordinates: 44.665, -114.220

Sheet flooding and minor ice jam flooding occurred throughout March as snow began to melt with the warmer temperatures along with periods of rain the latter half of the month. County road and field damage occurred with damage estimates over 60 thousand dollars.

Flood, Blaine

When: March 13, 12:00 PM MST to March 31, 11:00 PM MST
Where: Blaine County, 15 mi N of Ketchum to 10 mi W of Sun Vly
Cause: Heavy Rain / Snow Melt
Property damage: $155,000
Reported by: Emergency Manager
Coordinates: 43.897, -114.370

Warmer temperatures caused rises in the Wood River and period of rain embedded as well and flooding began in Bellevue on March 13th. Spruce Street in Bellevue flooded with Pero Road closed on the 15th. By the 27th the following roads in Blaine County were all reported closed: Democrat Gulch, Colorado Gulch, Road Canyon, Quigley, Muldoon Canyon, Rock Creek, Camp Creek, Croy Creek. Two homes in the Warm Springs area flooded along with adjacent barns and buildings. Estimated march damage in the county was seet at $155,000.

Flood, Caribou

When: March 13, 12:00 PM MST to March 31, 11:00 PM MST
Where: Caribou County, 5 mi SW of Bancroft to 5 mi E of Bancroft
Cause: Heavy Rain / Snow Melt
Property damage: $65,000
Reported by: Emergency Manager
Coordinates: 42.669, -111.940

Heavy rain added to snow melt to cause extensive sheet flooding in the Bancroft and Chesterfield areas with extensive damage to back roads which became unpassable. Damage estimates in the county rose above 60 thousand dollars.

Flood, Fremont

When: March 14, 5:00 AM MST to March 31, 11:00 PM MST
Where: Fremont County, Macks Inn to 10 mi W of St Anthony
Cause: Heavy Rain / Snow Melt
Property damage: $55,000
Reported by: Emergency Manager
Coordinates: 44.500, -111.330

Extensive flooding from snow melt and rain occurred in Fremont County. A lot of the flooding came on the 22nd including extensive sand dune wash out at the Saint Anthony Sand Dunes. Some damage to county roads occurred during the month with some field flooding as well.

Flood, Madison

When: March 14, 10:00 AM MST to March 31, 11:00 PM MST
Where: Madison County, Edmonds to 25 mi WNW of Plano
Cause: Heavy Rain / Snow Melt
Property damage: $1.3 million
Reported by: Emergency Manager
Coordinates: 43.920, -111.880

Extensive snow melt combines with heavy rains to create extensive sheet flooding problems in Madison County. 200 miles of county roads were washed out or damaged. the worst of it came on March 22nd with heavy rains over the county. The majority of the road damage was in the eastern part of the county. The state of Idaho declared Madison County a disaster area on March 19th. Damage estimates on mainly the roads by county officials exceeded one million dollars. Rocky Hollow road was destroyed.

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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

The same day elsewhere

Every storm in Idaho in 2018 Every state in 2018 This day in weather history Warnings in Idaho, March 2018

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: 747610, 747602, 747615, 747601, 747605, 747619, 747624.