Wyoming-Montana Water Science Center
Flooding and High-Flow Conditions in Wyoming and Montana Active
By Wyoming-Montana Water Science Center March 26, 2018
Greybull River near Basin, Wyoming
N F Flathead River at Blankenship Bridge near Columbia Falls, MT
Swiftcurrent Creek at Many Glacier, MT
Nov. 7, 2006 @ 1400 hrs
Wind River near Crowheart, WY
June 15, 2017 @ 13,300 ft3/s
The USGS monitors flood and high-flow conditions at more than 300 streamgages across Montana and Wyoming. Water level and flow information are used by the National Weather Service (NWS) to make accurate flood forecasts. High-flow conditions are expressed as percentiles comparing current (within the past few hours) instantaneous flow to historical daily mean flow for all days of the year.
A percentile is a value on a scale of one hundred that indicates the percent of a distribution that is equal to or below it.
"<95" indicates that the estimated streamflow is less than the 95th percentile for all days of the year,
"95-98" indicates that the estimated streamflow is between the 95th and 98th percentiles for all days of the year,
">=99" indicates that estimated streamflow is greater than the 99th percentile, and
"Not ranked" indicates that a flow category has not been computed. Common reasons for a "Not ranked" category are insufficient historical data or no current streamflow estimates.
Flood stages are determined by the NWS; not all USGS streamgages have flood stages. A depiction of other streamgages at or above flood stage is available the NWS River Conditions Map.
Current Flooding and High-Flow Conditions:
(Current-conditions data are provisional and subject to change)
Wyoming:
Map: Flood and high flows
Data table: Locations above flood stages
Map: Current streamflow conditions vs historical streamflows
Flood of August 1, 1985 in Cheyenne, WY
Floods of May 1978 in southeastern Montana and northeastern Wyoming
Montana:
Floods of May 1981 in west-central Montana
Floods of June 1964 in northwestern Montana
Devastating floods across much of the U.S. were severe and unrelenting during the spring and summer of 2011. When floods happen, USGS crews are among the first-responders. Often working in dangerous conditions, USGS scientists measure streamflow and river levels, repair and install streamgages, measure water quality and changes in sediment flow, and assess river changes. From flood forecasts to difficult decisions about flood management, science is critical for flood preparations and response.
How can a 100-year flood strike twice in 15 years? This is a downloadable poster discussing the meaning and use of probability language in flood characterization.
Poster: 100-Year Flood--It's All About Chance
Brian L Loving
Deputy Center Director for Observing Systems
bloving@usgs.gov
Floods and Droughts
Below are other science projects associated with floods and high-flows in Wyoming and Montana.
The 1972 Black Hills-Rapid City Flood
The 1972 Black Hills-Rapid City Flood Revisited
Dakota Water Science Center
Black Hills Area Floods - 1877 to 1890
Black Hills Area Floods - 1877 to 1890Look under the Multimedia table for pictures and more information regarding the event date and location, flow data (if available), a brief summary of the event, and links to available photographs or scanned newspaper articles.
Below are data or web applications associated with floods and high-flows in Wyoming and Montana.
USGS Peak Streamflow Data
The National Water Information System (NWIS) is the USGS water data portal where you can find a wealth of historic and real-time data related to floods. The NWIS website also is where you can query peak streamflow data by station, state (Wyoming or Montana), or region.
FloodWatch - View flood and high-flow conditions.
The USGS FloodWatch website is a map-based resource from USGS WaterWatch that gives users hourly visual updates for flood conditions at over 3000 locations across the United States (Wyoming or Montana). Learn how to use FloodWatch.
Surface-water data for Wyoming
Real-time, daily, peak-flow, field measurements, and statistics of current and historical data that describe stream levels, streamflow (discharge), reservoir and lake levels, surface-water quality, and rainfall in Wyoming. Surface-water data are collected and stored as either discrete field-water-level measurements or as continuous time-series data from automated recorders.
Surface-water data for Montana
Real-time, daily, peak-flow, field measurements, and statistics of current and historical data that describe stream levels, streamflow (discharge), reservoir and lake levels, surface-water quality, and rainfall in Montana. Surface-water data are collected and stored as either discrete field-water-level measurements or as continuous time-series data from automated recorders.
Below are publications associated with floods and high-flows in Wyoming and Montana.
Montana StreamStats
About this volumeMontana StreamStats is a Web-based geographic information system (http://water.usgs.gov/osw/streamstats/) application that provides users with access to basin and streamflow characteristics for gaged and ungaged streams in Montana. Montana StreamStats was developed by the U.S. Geological Survey (USGS) in cooperation with the Montana Departments of Transportation, Environmental Qua
Water Resources, Wyoming-Montana Water Science Center
Filter Total Items: 52
Publication Type (field_pub_type)
TypeArticleBookBook ChapterConference PaperOtherReportThesis
Release Date (field_release_date)
Year2022202120202019201820172016201520142013201220112010200920082007200620052004200320022001200019991998199719961995
Water-surface profile and flood boundaries for the computed 100-year flood, lower Salt River, Lincoln County, Wyoming
The water-surface profile and flood boundaries for the computed 100-year flood were determined for a part of the lower Salt River in Lincoln County, Wyoming. Channel cross-section data were provided by Lincoln County. Cross-section data for bridges and other structures were collected and compiled by the U.S. Geological Survey. Roughness coefficients ranged from 0.034 to 0.100. The 100-year flood w
Flood boundaries and water-surface profiles for the computed 50-, 100-, and 500-year floods, Childs Draw and tributary, near Cheyenne, Wyoming, August, 1991
Flood boundaries and water-surface profile for the computed 100-year flood, Swift Creek at Afton, Wyoming, 1986
Flood flows on Swift Creek near Afton, Wyoming, were analyzed. Peak discharge with an average recurrence interval of 100 years was computed and used to determine the flood boundaries and water surface profile in the study reach. The study was done in cooperation with Lincoln County and the Town of Afton to determine the extent of flooding in the Town of Afton from a 100-year flood on Swift Creek.
Floodflow characteristics at bridge site on Interstate 80, the Green River near Green River, Wyoming
Hydrologic effects of hypothetical earthquake-caused floods below Jackson Lake, northwestern Wyoming
Jackson Lake, located in Grand Teton National Park, Wyoming, is in an area of seismic instability. There is a possibility of flooding in the Snake River downstream from Jackson Lake Dam in the event of a severe earthquake. Hypothetical floods were routed 38 miles (61 kilometers) downstream from the dam for three cases: (1) Instantaneous destruction of the dam outlet structure, (2) instantaneous de
Relations between total-sediment load and peak discharge for rainstorm runoff on five ephemeral streams in Wyoming
Total-sediment loads transported by ephemeral flows are a function of rainstorm energy and peak discharge. Rainstorm energy, estimated by rainfall intensity, is the primary mechanism for soil-particle detachment. Vegetation, soil cohesiveness, and land slope also are related to the amount of sediment detached, but these factors remain nearly constant, except for seasonal or human-induced changes i
Analysis of runoff from small drainage basins in Wyoming
A flood-hydrograph study has defined the magnitude and frequency of flood volumes and flood peaks that can be expected from drainage basins smaller than 11 square miles in the plains and valley areas of Wyoming. Rainfall and runoff data, collected for 9 years on a seasonal basis (April through September), were used to calibrate a rainfall-runoff model on each of 22 small basins. Long-term records
Peak-flow characteristics of Wyoming streams
Peak-flow characteristics for unregulated streams in Wyoming are described in this report. Frequency relations for annual peak flows through water year 2000 at 364 streamflow-gaging stations in and near Wyoming were evaluated and revised or updated as needed. Analyses of historical floods, temporal trends, and generalized skew were included in the evaluation. Physical and climatic basin characteri
Using the National Flood Frequency Program, version 3; a computer program for estimating magnitude and frequency of floods for ungaged sites
The National Flood Frequency Program, version 3 : a computer program for estimating magnitude and frequency of floods for ungaged sites
For many years, the U.S. Geological Survey (USGS) has been developing regional regression equations for estimating flood magnitude and frequency at ungaged sites. These regression equations are used to transfer flood characteristics from gaged to ungaged sites through the use of watershed and climatic characteristics as explanatory or predictor variables. Generally, these equations have been devel
Flood Event Viewer
During large, short-term events, the USGS collects streamflow and additional data (including storm tide, wave height, high-water marks, and additional sensor deployments) to aid in documenting flood events. The USGS Flood Event Viewer provides convenient, map-based access to downloadable event-based data.
Water Resources, New Jersey Water Science Center, Upper Midwest Water Science Center
Below are news stories associated with floods and high-flows in Wyoming and Montana.
See Social Media
Study Links Major Floods in North America and Europe to Multi-Decade Ocean Patterns
The number of major floods in natural rivers across Europe and North America has not increased overall during the past 80 years, a recent study has concluded. Instead researchers found that the occurrence of major flooding in North America and Europe often varies with North Atlantic Ocean temperature patterns.
Climate Research and Development Program, Groundwater and Streamflow Information Program, New England Water Science Center, Communications and Publishing
USGS Measures Flooding in Missouri
U.S. Geological Survey field crews are measuring flooding on rivers and streams across southwestern and southern Missouri and northeast into the St...