Debris Flow — Kootenai, Idaho

2017-03-15 to 2017-03-31 · near Spirit Lake, Kootenai, Idaho

Event narrative

Snow melt and periodic heavy rain during the month of March caused numerous debris flows and areal flooding issues through out the county. A debris flow near Harrison forced the evacuation of a residential neighborhood with the land continuing to move through the beginning of April. Over 20 roads through out the county were washed out or cut by debris flows and numerous homes experienced basement and first floor flooding. Kootenai County was included in a Presidential Disaster Declaration as a result of the damage inflicted by this episode.

Wider weather episode

March was a very wet month over the Idaho Panhandle. A series of moist Pacific storm systems brought periodic heavy rain to the region in addition to warmer temperatures which quickly melted low elevation snow pack. Bonners Ferry recorded 4.58 inches of precipitation for the month which was 2.92 inches above normal. Coeur D'Alene received 4.38 inches which was 2.04 inches above normal and The University of Idaho at Moscow recorded 7.19 inches which was 4.50 inches above normal.

All of this water quickly saturated the ground leading to numerous debris flows in steep terrain and widespread flooding in fields and low spots. Numerous roads were flooded or cut by debris flows through out the Idaho Panhandle during the second half of March.

The St. Joe River, the Cour D'Alene River and Palouse River as well as numerous smaller streams and lakes rose above Flood Stage during this event. Lake Coeur D' Alene and the Spokane River draining Lake Coeur d'Alene also crested above Flood Stage damaging numerous docks, parks and homes along the shore line and river.

Idaho State declared a State of Emergency for seven counties in North Idaho to assist recovery crews in obtaining resources to repair damage to area roads and other infrastructure. These counties were also included in a Presidential Disaster Declaration as a result of this very wet period.

View location on OpenStreetMap → (47.9699, -117.0401)

Source: NOAA Storm Events Database, event_id 688984. Narrative written by the NWS forecast office that issued the report.