An Atmospheric River brought a persistent stream of moisture off the Pacific Ocean to West Central Idaho April 6-10. Rainfall totals of 2 to 5 inches were measured at many weather stations while snow melt added 1 to 3 inches of melt-water to the runoff.
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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 BOI wrote it up.
An Atmospheric River brought a persistent stream of moisture off the Pacific Ocean to West Central Idaho April 6-10. Rainfall totals of 2 to 5 inches were measured at many weather stations while snow melt added 1 to 3 inches of melt-water to the runoff. Main stem river flooding, flash flooding, and small stream flooding occurred during the event with record or near record crests observed on a number of waterways. In addition, debris flows on past years wildfire burned areas, rock slides, and mudslides occurred.
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 Boise, ID wrote its last area forecast discussion before the first event at Apr 7, 2:23 AM MST, 4 hours 7 minutes earlier.
Area Forecast Discussion National Weather Service Boise ID 323 AM MDT Sun Apr 7 2019 .SHORT TERM...Today through Wednesday...Wet this morning in central and northern areas as a surge of moisture comes in from the Pacific. Locally heavy rain in Idaho north of the Snake Basin. Relatively lighter rain will continue this afternoon through Monday morning, then increase again late Monday through Tuesday morning, and also cover southern areas, as an upper trough comes in from the Pacific. Heavy rains are possible at that time, and instability will generate at least a slight chance of thunderstorms Monday afternoon and evening. Total rainfall today through Tuesday north of the Snake basin will be 1.00 to 2.75 inches, and along with snowmelt as high as 8500 feet, will cause rivers to rise. Mich less rain is expected from the Snake Basin southward and in southeast Oregon, where totals should only be .20-.50 inch. Cold front Monday night will be followed by lowering snow levels and decreasing snowmelt at the higher elevations. Lighter rain and snow showers will continue Tuesday as the Pacific trough moves through, but models generate significant west winds Tuesday afternoon as surface high pressure builds inland. Wednesday looks breezy and cool with scattered light rain and snow showers continuing. .LONG TERM...Wednesday night through Sunday...An upper trough continues to deepen over the region as northwest flow lowers temperatures through mid-week. Unsettled flow persists on Thursday as a low pressure system migrates southward along the Pacific coast. Much of the area will see widespread showers with snow levels between 3500-4500 ft MSL. Once this system clears the region by Friday night, a ridge building over the PacNW will cause conditions to dry as temperatures bounce back to about normal. By Sunday, the ECMWF quickly progresses another upper low through the region with widespread precip, whereas the GFS maintains a dry ridge until Monday. PoPs were weighted towards the ECMWF at the end of the period as the CMC showed a similar progression. && .AVIATION...Mostly VFR with MVFR within showers and mountain obscurations. Rain increasing in coverage from west to east becoming widespread across western Idaho this morning. Surface winds: south 5-15 kts with higher winds up to 20 kts along NV border in Oregon. Gusts up to 30 kts through 08/0z mainly across Oregon. Winds aloft to 10k feet MSL: southwest-west 40-50 kts. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. .AVIATION...Mostly VFR with MVFR within showers and mountain obscurations. Isolated rain will continue for remainder of the evening, increasing in coverage from west to east after 03z becoming widespread on the Idaho side by early morning. Surface winds, southeast-southwest 5-10kts with increase in afternoon hours to 15- 20kts with gusts 25-30kts. Winds aloft to 10k feet MSL, southwest- west 40-50kts. && .PREV DISCUSSION... SHORT TERM...Tonight through Tuesday...A moist Pacific plume will surge inland tonight and bring significant precipitation to northern portions of the forecast area through Tuesday. Snow levels will rise from around 6500 feet tonight to around 8000 feet on Sunday and remain at least 8000 feet through Monday evening. The snow levels will then lower to around 5500 feet behind a cold front on Tuesday. Precip totals of 1 to 3 inches are possible in the northern mountains (including Baker County, Central Idaho) with much lower amounts of an inch or less elsewhere. The combination of rain and snowmelt will cause rises on rivers, creeks, and streams with minor flooding possible (see the Hydrologic Outlook for details). Instability ahead of the cold front will bring a slight chance of thunderstorms Monday afternoon and evening. Temperatures will be above normal through Monday, lowering to below normal on Tuesday. Northwest winds will increase on Tuesday with the arrival of cooler air behind the cold front, becoming windy by the afternoon. LONG TERM...Tuesday night through Saturday...Long range models continue to be in good agreement indicating an upper low swings through the region Tuesday night bringing breezy conditions to most locations. A northwesterly flow develops for the remainder of the extended as an upper ridge amplifies near 150-160W. Cooler conditions expected with lower snow levels (3500-5000 feet). Showers move back into the region Thursday morning as an upper low drops into the Pacific Northwest. How this low progresses out of the area is still in question as the ECM keeps troughiness over the region Friday into early Saturday, whereas the GFS drops the low into the SW states and builds an upper ridge over the Pac NW. Models do come back into agreement Saturday afternoon as another low pushes into the Pac NW coast. && && www.weather.gov/Boise www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...LC LONG TERM....AL AVIATION.....AL
The national radar mosaic for the moment the first event began.
3 flood. Local standard time, as filed.
The Adams County emergency manager reported flooding and flash flooding including debris flow throughout the county.
The Valley County emergency manager reported flooding and flash flooding including debris flow throughout the county.
The Washington County emergency manager reported moderate flooding near the U.S. Highway 95 bridge in Weiser. The flooding caused extensive damage and the closure of the highway for 4 days.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2019Every state in 2019This day in weather historyWarnings in Idaho, April 2019
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: 813450, 813455, 813447.