PROJECT ALERT NOTICE (ID) Minor to Moderate flooding throughout Idaho

Date: Thu, 04 May 2023 15:56:41 EDT

Summary: Warm weather and heavy snowpack have swollen many rivers and streams to at/near flood levels

Significantly above average temperatures from April 27 to May 3 and above average snowpack (Boise basin is at to near record snowpack) has made multiple site at or near NWS flood stage. A cold(er) front will likely return temperatures to near normal temperatures May 4 to the foreseeable future causing many of these sites to recede though potential precipitation associated with the front could be cause for concern.

According to USGS Waterwatch
35 sites have exceed the 90th percentile
9 sites have exceeded the highest value for this date in the period of record.

5 sites are above action stage
5 sites are above minor flood stage
1 site is above moderate flood stage (13075500, Portneuf River at Pocatello, ID)

Portneuf River is expected to crest near major flood stage Friday May 5 and continue at the level through May 11.

St. Joe River is expected to crest below moderate flood stage on May 6.

Coeur D' Alene River is expected to crest above the minor flood stage on Saturday May 6.

Big Wood River is expected to crest near moderate flood stage at 2700 cfs on Friday, May 5.

Crews from all IDWSC field offices have been, and are, in the field making needed high flow measurements.

All gages are operational and no damage has been reported.

1 newly established gage has experienced a peak of record.
3 newly established gages are in need of rating extensions.

In communication with Idaho Water Districts, IDWR, USACE and USBR as needed to prioritize stream flow measurements.

No additional help is needed at this time.