PROJECT ALERT NOTICE (MT WY) Minor to moderate flooding Eastern Montana and Northeastern Wyoming

Date: Sat, 23 Mar 2019 12:42:19 EDT

Summary: Minor to moderate flooding from snowmelt and ice-jams is occurring in eastern Montana and northeastern Wyoming.

Lowland snowmelt runoff and ice-jam flooding is causing current gage-heights at nine (9) U.S. Geological Survey streamgages in northeastern Montana and northeastern Wyoming to exceed National Weather Service minor and moderate flood stage levels. Ice-jam flooding from earlier in the week is receding on Little Powder and Belle Fourche rivers in northeastern Wyoming and the Tongue and Yellowstone rivers in southeastern Montana.

Annual exceedance probabilities have not been determined. Discharge measurements at 2 streamgages in northeastern Wyoming with 46 to 65 years of data were the second and third largest on record.

No streamgages have been damaged or destroyed.

Three crews were deployed Friday March 22 for flood- and high-flow measurements. Streamflow data currently qualified as ice-effected were validated with field observations. One crew is deployed this weekend to complete direct measurements at sites that are part of a crest-stage gage network in north-central and northeastern Montana.

Cooperators, stakeholders, and the general public are being kept informed by multiple methods including social media. Photographs of hydrographers measuring flood- and high-flows with text for context and links to data are being posted at Twitter and Instagram accounts @USGS_WY and @USGS_MT.


WaterWatch flood map for Northeastern Montana