National Weather Service United States Department of Commerce

A Below Average Flood Potential From Ice Jams And Spring Snowmelt

 

Conditions as of:  March 09, 2023  

 

Area Covered 

This Spring Flood and Water Resource Outlook is for the North Platte Hydrologic Service Area, which covers western and north central Nebraska. The river basins include: the North Platte and South Platte Rivers and the Platte River in western Nebraska, Frenchman Creek and Stinking Water Creek in southwest Nebraska, the Loup and Dismal Rivers in the Sandhills of Nebraska, and portions of the Elkhorn and Niobrara Rivers in north central Nebraska.

Current Flooding

To obtain the latest watches, warnings, statements, and advisories, go to the NWS North Platte Advanced Hydrologic Prediction Service

Flood Outlook Summary

A below average flood potential is expected from spring snowmelt and ice jams. Above normal to much above normal snowfall occurred across western and north central Nebraska in December and January with below normal snowfall in February. The majority of this snowfall has melted. There is also a below average flood potential from ice jams. Ice jams will remain possible until the ice is off the rivers. This would be more likely to occur on the Niobrara River Basin, where ice still remains. Once the frost is out of the ground and the ice is off the rivers, the flood potential from ice jams will end.

The potential for rainfall induced flash flooding is not quantifiable. This type of flooding is most likely to occur during the later spring and summer months.

Snow Cover and Mountain Snowpack

As of March 9th, snow cover ranged from 2 to 6 inches across portions of northern Nebraska, including the Niobrara River Basin. Snow cover was only a trace to an inch across southwest and central Nebraska. Snow water equivalents ranged from a half inch to an inch in areas of highest snow cover. March and April are typically snowy months, so additional snowfall is possible.

The snowpack in the North Platte and South Platte River Basins in Colorado and Wyoming were above average, with snow water equivalent ranging near 125 percent of average for the North Platte Basin and 104 percent of average for the South Platte Basin. These values are above last year. A below average flood potential is expected from mountain snowmelt runoff.

Reservoir Conditions

Normal operations are ongoing at reservoirs along the North Platte River for this time of year. Releases from these dams have been limited through the winter months, with inflows generally coming from melting snow. Because of these operations, reservoir levels have risen through the winter months. The current reservoir storage across Wyoming, as well as Lake McConaughy, are below average for this time of the year.

Soil Conditions

Despite above normal snowfall this winter, soil moisture across western and north central Nebraska is below average, ranging from 1.5 inches to near 2.5 inches below normal. The U.S. Drought Monitor indicates that moderate to extreme drought conditions persist across north central Nebraska and severe to extreme drought conditions across much of southwest Nebraska. Soil temperature sensors indicate most areas have a 4 inch soil temperature in the lower 30s. Frost depths were generally 3 to 7 inches.

Calculated Soil Moisture Anomaly
Modeled Snow Moisture from Climate Prediction Center

 

Latest 1 Day
Soil Temperature
Latest 7 Day
Average Soil Temperature
One-day average soil temperatures Seven-day average soil temperatures
Soil Temperatures Data from University of Nebraska Lincoln Crop Watch

 

River and Lake Ice Conditions

Monthly average streamflow was average to above average across the central and northern Sandhills, including the Niobrara and Loup River Basins. Below average to much below average streamflow was indicated across the southeast panhandle and southwest Nebraska, including the Platte River Basin, and Frenchman Creek Basin. Ice remains on all lakes, rivers, and streams.

Monthly Average Streamflow

 

 

Streamflow Mapping provided by the USGS

 

Seasonal Precipitation

Precipitation so far this water year, since October 1, 2022, has ranged from near normal to much above normal across much of the hydrologic service area. Precipitation amounts ranged from 2 to 4 inches across the western Sandhills and southwest Nebraska, to 4 to 6 inches across Custer County northward across the eastern half of north central Nebraska. These amounts ranged from as much as 100 to 150 percent of normal across much of the hydrologic service area.

Nebraska
Percent of Normal Precipitation since October 1
Nebraska
Precipitation since October 1
Image of Percent of Normal Precipitation for the Water Year Current Climate Summary Map
Precipitation Maps from the High Plains Climate Center

 

Precipitation and Temperature Outlook

Water temperatures in the tropical Pacific Ocean continue to be slightly below average, with weak La Nina conditions. The outlook indicates ENSO neutral conditions are likely to develop during the March through April period. For the spring months, this weather pattern will typically favor cooler and wetter conditions  across the Pacific northwest and Northern Plains and warmer and drier conditions favored across the southwestern U.S. and southern Plains.  Equal chances for above, below, or average temperatures and precipitation are predicted across the Central Plains.  


According to the Climate Prediction Center, the latest 8 to 14 day outlook calls for below normal temperatures and leans slightly towards above normal precipitation. 

8 - 14 Day Temperature Outlook 8 - 14 day Precipitation Outlook

 

The latest 30 day outlook for March calls for equal chances for above, below, or normal temperatures and precipitation.

Temperature Outlook Precipitation Outlook

 

According to the Climate Prediction Center, the latest 90 day outlook for March, April and May indicates there are equal chances for above, below, and normal temperatures and precipitation this spring. 

Three Month Temperature Outlook Three Month Precipitation Outlook

 

More Outlooks are available at the Climate Prediction Center Temperature and Precipitation Outlooks webpage

 

Questions or Comments

If you have any questions or comments about this spring flood and water resource outlook please contact,

Kenneth Roberg
North Platte HSA Focal Point
National Weather Service
5250 East Lee Bird Drive
North Platte, NE 6910
Telephone 308-532-4936
E-mail kenneth.roberg@noaa.gov
 or 
Melissa Smith
Service Hydrologist
National Weather Service
300 East Signal Drive
Rapid City South Dakota 57701
Telephone 605-341-9271
E-mail melissa.smith@noaa.gov