Heavy rain fell from thunderstorms and produced a couple of debris flows Sunday evening.
Every event with a place to put it. Tap one for its entry below.
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 episode as NWS MSO wrote it up.
Heavy rain fell from thunderstorms and produced a couple of debris flows Sunday evening.
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 4, 1:20 PM MST, 6 hours 40 minutes earlier.
Area Forecast Discussion National Weather Service Missoula MT 220 PM MDT Sun Jun 4 2023 .DISCUSSION... A marginally unstable atmosphere will remain over the Northern Rockies through this evening, with terrain enhanced showers and thunderstorms present (most notable south of Montana Highway 200 corridor). Adding to this scenario, high-resolution models suggest that a closed low pressure circulation over the northern Great Basin/Snake River Plain will meander north and reach Lemhi County/southwest Montana by this evening. This low pressure will enhance some of the convection, however the high-resolution models are struggling to reach consensus on storm initiation. There is a 5 percent probability of excessive rainfall (flash flood threat) across Lemhi County/southwest Montana through this evening. Once sunset nears this evening, the loss of daytime heating will likely inhibit further shower and thunderstorm development for western Montana. However, most near-term models depict showers and isolated nocturnal thunderstorms spreading north/west over north central Idaho throughout tonight. By Monday afternoon, shower and isolated thunderstorm activity associated with a weak closed low pressure circulation is expected to spread eastward from north central Idaho to most of western Montana. Daytime heating will intensify convection, however the lack of strong flow aloft will prevent much storm organization. Nevertheless, 5 percent probability of excessive rainfall remains for Lemhi County/southwest Montana throughout Monday daytime. By Monday evening, models suggest that the closed low pressure will become an open wave (low pressure trough) and move northeast into Canada. Weak high pressure is anticipated to be present over the Northern Rockies Tuesday to Wednesday, however this will not necessarily translate to dry conditions across the region. National Blend of Models components point toward daytime temperatures to peak on Wednesday, with low elevations in the 80s (western Montana) to low 90s (north central Idaho). The increase in surface temperatures will allow rapid afternoon thunderstorm development (particularly near the Continental Divide across Lemhi County/southwest Montana). Much of this thunderstorm activity will be phased with daytime heating, translating to convection dissipating shortly after sunset each evening. Thursday through next weekend, models suggest that another closed low pressure circulation will develop and meander around the Great Basin. The movement of atmospheric moisture counterclockwise around the low pressure will provide daily showers and thunderstorms to most of the Northern Rockies. There is generally a 60-80 percent probability of 0.25" or greater rainfall for most locations Thursday- Saturday. For Thursday specifically, there is 5-15 percent probability of excessive rainfall for much of the Northern Rockies (with emphasis for southwest Montana along the Continental Divide). The increased moisture and cloud cover will suppress daytime temperatures, while simultaneously maintaining relatively warm overnight temperatures. In fact, National Blend of Models suggest near-record overnight warmth Thursday-Saturday. && .AVIATION... Showers and thunderstorms will continue to develop across Northern Rockies air space through 05/0000Z, with most activity occurring near KMSO and south. Watch for isolated occurrences of brief, heavy rain to reduce visibility. Also, erratic wind gusts to 30 knots will be common near any developing thunderstorm. After 05/0000Z, a weak closed low pressure circulation will approach north central Idaho from the south, sparking nocturnal showers and isolated thunderstorm activity (mainly west of KMSO and south of KHRF) through 05/1500Z. Patchy fog will develop Monday morning for valley locations that receive rainfall late Sunday and experience clearing overnight. Past Monday morning, showers and thunderstorms are expected to proliferate across the remainder of northern Rockies air space, as the closed low pressure eventually continues east of the Continental Divide after 06/0600Z. Terrain obscurations will be closely phased with the evolution of showers and thunderstorms, as well as Monday morning patchy valley fog. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. &&
The national radar mosaic for the moment the first event began.
2 debris flow. Local standard time, as filed.
The Idaho Transportation Department reported that a major landslide occurred which covered US-93 in both directions near Warm Springs Road at milepost 282 near Elk Bend.
The Salmon-Challis National Forest reported that a landslide had fully blocked the Salmon River Road, one mile southwest of Pine Creek.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2023Every state in 2023This day in weather historyWarnings in Idaho, June 2023
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: 1094957, 1094961.