Flood in Shoshone County, Idaho

Several days of moderate rain and excessive snow melt lead to numerous road washouts, plugged culverts, minor rock slides, flooded basements, and impassible roads from flooding across Shoshone County. These roads included: Bear Creek, Ross Ranch, Riverview, French Gulch, Old CDA River, Golf Course, Kelly Gulch, Wier Gulch, Trapper Creek, Upper Pine Creek Bridge, Lynch Gulch, Galena Gulch, Daly Gulch, Nine Mile, Placer Creek, Revenue, Gulch, Mullan, Bingville, Willow Acres, Sunny Slopes, Nuchols Gulch, Tank Creek, North Side, Markwell (between 6th and 7th), and numerous sections of the Saint Joe River Road (Forest Road 50). In addition, the flooding resulted in waste water overflow in the communities of Mullan, Osburn, and Smelterville with no known health risks at the time of the report.

A stagnant longwave pattern featuring a broad trough off the Pacific Northwest Coast and upper-level ridge over the Central US resulted in a parade of moist storm systems tracking through the Inland Northwest from March 28th through the 31st. Each storm system deposited 0.25 to 0.75 inches of rainfall across most locations in the Idaho Panhandle with three day rainfall totals ranging from one to three inches. This concluded record setting precipitation totals for the month of March. With soils already saturated from heavy rain just a few days earlier and above normal snowpack still in place in the mountains, portions of North Idaho experienced numerous floods, road washouts, and debris flows. The most significant damage occurred in Bonner County which involved a train track washout, train derailment, and washout of a hundred foot length of road near Cocolalla Lake.