Name: Flooding in Idaho, May 1 to 31, 2017
Start: 2017-05-01T00:00
End: 2017-05-31T23:59
Location: Idaho

Where it happened

Every event with a place to put it. 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: 0
Property damage: $2.8 million
Crop damage: None recorded
Events: 2

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.

What happened

The episode as NWS BOI wrote it up.

The Boise River continued to be in flood during the entire month of May due to planned release at Lucky Peak.

What forecasters said that day

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 30, 7:42 PM MST, 4 hours 18 minutes earlier.

Area forecast discussion, Apr 30, 7:42 PM MST, 4 hours 18 minutes before

Area Forecast Discussion
National Weather Service Boise ID
842 PM MDT Sun Apr 30 2017

.DISCUSSION...Dry conditions expected through Monday afternoon
under northwest flow aloft. Next wave moves through the region
Monday evening bringing a short period of light showers. A ridge
then builds across the western US on Wednesday, bringing a drying
and warming trend, and temperatures rising to around 15 degrees
above normal by Thursday. High temperatures will be below records
with low to mid 80s expected on Thursday afternoon. No changes to
the current forecast.

&&

.AVIATION...VFR with scattered mid level clouds across SW Idaho and
SE Oregon tonight through Monday. Sky will become overcast on Monday
afternoon with isolated rain showers moving through the area on
Monday evening. Surface winds: west-northwest 10 to 15 kts. Winds
aloft near 10k feet MSL: northwest around 25 kts.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Tuesday...Isolated showers will
continue through this evening with passage of the shortwave and
cold front. Showers will produce very little rainfall less the a
couple of hundreths. Winds will increase from the northwest this
evening with the frontal passage. The front will move across
Southeast Oregon by 03z and Southwest Idaho by 09z. Northwest
winds will blow 15 to 30 mph in the Upper Treasure Valley and
western Magic Valley, 10 to 20 mph in eastern Oregon, and 5 to 15
mph elsewhere. Another shortwave moves across the Pacific
Northwest Monday afternoon/evening for more showers. Upper level
ridge begins to build eastward on Tuesday beginning the drying and
warm trend. Temperatures gradually warming for the low 60s Monday
into the mid to upper 60s on Tuesday.

LONG TERM...Tuesday night through Sunday...Upper level ridge will
strengthen as it shifts eastward - from near the coast on Tuesday
and into Idaho on Thursday. High temperatures will warm 5-10 degrees
each day, with valley highs in the 70s to lower 80s on Thursday.
Models agree that an upper trough will approach the PacNW late in
the week, but a lot of uncertainty for next weekend pertaining to
the development and track of an upper low. Temperatures will remain
well above normal late in the week, trending down to near normal
next weekend. Dry weather will accompany the ridge Tuesday through
Thursday, followed by a chance of showers and thunderstorms for the
remainder of the extended period.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise

DISCUSSION...KA
AVIATION.....JB
PREV SHORT TERM...JDS
PREV LONG TERM....BW/WH

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

2 flood. Local standard time, as filed.

Flood, Ada

When: May 1, 12:00 AM MST to May 31, 11:59 PM MST
Where: Ada County, Barber to 0.86 mi SSW of Barber
Cause: Planned Dam Release
Property damage: $2.0 million
Reported by: Official NWS Observations
Coordinates: 43.570, -116.120

The Boise River remained in flood during the entire month of May due to planned release from Lucky Peak dam. Regulated flows were above flood stage for 101 days resulting in extensive damage to the Greenbelt and Nature Trail paths. Extensive flood fight efforts continued in the Eagle Island area to prevent a pit capture. Widespread flooding continued on Eagle Island in the Riviera Estates area where several homes were surrounded by water and low lying roads were inundated. Large portions of Ann Morrison Park, Barber Park, and Marianne Williams Park were impacted by flood waters. Some residential streets continued to be impacted by flood waters, especially in the Garden City Warehouse District and on Eagle Island. A pit capture occurred just downstream of Eagle Island causing a major shift in the river channel. Streets in the Stonebriar development just downstream of the Highway 16 bridge were inundated by water. Severe bank erosion and large trees washed into the river caused problems in the river channel and at some bridge crossings.

Flood, Canyon

When: May 1, 12:00 AM MST to May 31, 11:59 PM MST
Where: Canyon County, Middleton to 0.59 mi W of Maddens
Cause: Planned Dam Release
Property damage: $750,000
Reported by: Official NWS Observations
Coordinates: 43.700, -116.630

The Boise River remained in flood during the entire month of May due to planned release from Lucky Peak dam. Regulated flows were above flood stage for 101 days resulting in extensive bank erosion and flooding of lowlands along the river.

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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

The same day elsewhere

More

Every storm in Idaho in 2017 Every state in 2017 This day in weather history Warnings in Idaho, May 2017

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: 702479, 702481.