Tornado and Debris Flow in Idaho, April 3 to 30, 1997

Name: Tornado and Debris Flow in Idaho, April 3 to 30, 1997
Start: 1997-04-03T20:00
End: 1997-04-30T23:59
Location: Idaho

April 3 to 30, 1997 · NWS BOI · 14 events in 9 counties and zones

5 flood, 3 heavy snow, 2 dust storm, 2 hail, 1 debris flow, 1 tornado, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. 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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 8
Property damage: $100
Crop damage: None recorded
Events: 14

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 radar

The Spokane radar (KOTX), 100 km away, was scanning. The volume nearest the first event began at 17:13 UTC.

Open the radar archive at this moment

Event by event

5 flood, 3 heavy snow, 2 dust storm, 2 hail, 1 debris flow, 1 tornado. Local standard time, as filed.

Heavy Snow, Boundary/Bonner/ X N Kootenai

When: April 3, 8:00 PM MST to April 4, 5:00 AM MST
Where: Boundary/Bonner/ X N Kootenai forecast zone
Coordinates: 48.247, -116.588 (the zone’s center; the record gives no point)

Heavy Snow, Shoshone

When: April 3, 8:00 PM MST to April 4, 6:00 AM MST
Where: Shoshone forecast zone
Coordinates: 47.265, -116.491 (the zone’s center; the record gives no point)

A strong Pacific storm system moved into Northern Idaho and dumped 5 inches of snow upon Sandpoint and Kellog.

Heavy Snow, Custer/Nw Butte/Nw Blaine

When: April 4, 6:00 PM MST to April 5, 10:00 AM MST
Where: Custer/Nw Butte/Nw Blaine forecast zone

This storm dumped heavy snow in the Salmon/Sawtooth Mountains of East Central Idaho with Arco reporting 6 inches of new snow, 6 to 7 inches in the Craters of the Moon area and 12 inches at Moore.

Debris Flow, Boundary/Bonner/ X N Kootenai

When: April 12, 12:00 AM MST to April 30, 11:59 PM MST
Where: Boundary/Bonner/ X N Kootenai forecast zone
Property damage: $100
Coordinates: 48.247, -116.588 (the zone’s center; the record gives no point)

Heavy snows melting in the Idaho Panhandle saturated soils and triggered numerous mud slides in Bonner and Boundary Counties. These mudslides cut local roads and disrupted traffic.

Flood, Kootenai T X N

When: April 20, 12:00 AM MST to April 30, 11:59 PM MST
Where: Kootenai T X N forecast zone
Coordinates: 47.675, -116.700 (the zone’s center; the record gives no point)

Spring rains and snowmelt caused the Coer d'Alene River and the St. Joe River to fluctuate above and slightly below flood stage for the remainder of April. Flooded roads and basements were the main problems associated with this minor flooding.

Flood, Shoshone

When: April 20, 12:00 AM MST to April 30, 11:59 PM MST
Where: Shoshone forecast zone
Coordinates: 47.265, -116.491 (the zone’s center; the record gives no point)

Minor flooding along the St. Joe River.

Tornado, Ada

When: April 20, 10:15 AM MST to 10:20 AM MST
Where: Ada County, 4 mi NW of Boise Terminal Arpt
Rating: F0
Path length: 0.2 mi
Path width: 30 yd
Coordinates: 43.600, -116.280

On the morning of April 20, a strong cold front moved across Southern Idaho . This cold front produced strong thunderstorms in the Boise area which spawned a short lived weak tornado. The tornado moved through a subdivision on the outskirts of Boise . Six houses suffered roof damage,fences were torn up and a trampoline was hurled 5 city blocks.

Dust Storm, Jefferson/Madison/W Bonneville/N Bingham/Se Butte

When: April 20, 2:00 PM MST to 2:30 PM MST
Where: Jefferson/Madison/W Bonneville/N Bingham/Se Butte forecast zone
Injuries: 8 direct, 0 indirect

A strong cold front swept across Eastern Idaho . Wind gusts to 58 mph accompanied the front and produced a dust storm on Interstate 15 north of Idaho Falls. 21 auto accidents and 8 injuries were blamed on poor visibilities caused by the blowing dust.i

Flood, Cassia T X N/S Power/Oneida

When: April 21, 1:00 PM MST to April 30, 11:59 PM MST
Where: Cassia T X N/S Power/Oneida forecast zone

Flood, Sw & Sc Bingham/X Nw Bannock/N Power

When: April 21, 1:00 PM MST to April 30, 11:59 PM MST
Where: Sw & Sc Bingham/X Nw Bannock/N Power forecast zone

A storm system brought .33 inches of rain to Pocatello on April 20th. heavier amounts probably fell in the surrounding mountains. The rains were enough to cause the Portneuf River to flood. Although a minor flood with no significant damage reported, the river remained slightly above flood stage for the remainder of the month.

Dust Storm, Jefferson/Madison/W Bonneville/N Bingham/Se Butte

When: April 27, 6:00 PM MST to 8:00 PM MST
Where: Jefferson/Madison/W Bonneville/N Bingham/Se Butte forecast zone

Strong winds over the Upper Snake River Plane created a dust storm which reduced visibilities low enough to force the closure of Interstate 84 north of Idaho Falls.

Flood, Jefferson/Madison/W Bonneville/N Bingham/Se Butte

When: April 28, 6:00 PM MST to April 30, 11:59 PM MST
Where: Jefferson/Madison/W Bonneville/N Bingham/Se Butte forecast zone

Snowmelt at higher elevations of the headwaters of the Henrys Fork of the Upper Snake River caused the Henrys Fork to rise slightly above flood stage for the remainder of the month. Little damage beyond flooded agricultural land was reported.

Hail, Canyon

When: April 30, 9:00 PM MST to 9:20 PM MST
Where: Canyon County, 3 mi S of Caldwell
Measured: 0.75 in hail
Coordinates: 43.620, -116.700

During the afternoon and evening of April 30 1997 a series of strong and severe thunderstorms moved into Southwest Idaho. 3/4 inch hail was reported just south of Caldwell , Idaho and 1 inch hail was reported in just west of the Boise Airport.

Hail, Ada

When: April 30, 9:15 PM MST to 9:20 PM MST
Where: Ada County, 2 mi W of Boise Terminal Arpt
Measured: 1 in hail
Coordinates: 43.570, -116.270

A weather spotter reported one inch hail with a thunderstorm near the Boise Airport.

What these are

Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.
Debris Flow: A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Dust Storm: Blowing dust that reduced visibility to a quarter mile or less.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

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

The same day elsewhere

Every storm in Idaho in 1997 Every state in 1997 This day in weather history The tornado archive for Idaho, 1997 Warnings in Idaho, April 1997

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: 5601477, 5601478, 5601476, 5600318, 5600319, 5600320, 5600230, 5600229, 5600231, 5600232, 5600233, 5600234, 5600321, 5600322.