This data collection of U.S. Geological Survey data releases provides the source data and results of flood frequency analyses and annual exceedance probability estimation for selected observed floods in Alaska and conterminous basins in Canada. The data include streamgage information, PeakFQ input and output, flood frequency parameters, flood frequency estimates for selected annual exceedance probabilities, and annual exceedance probability estimates for selected observed flood events.

This data release provides the source data and results of a flood frequency analysis for sites in the Mendenhall River Basin, Alaska, that was conducted using USGS PeakFQ software (Veilleux and others, 2014; Flynn and others, 2006). Data are provided for two streamgages that had at least 10 years of annual peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .EMF files), flood frequency parameters, and flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities. Flood frequency analysis for the Mendenhall River excluded annual peak-flow data affected by glacial lake outburst floods. These data were intended to support investigations of streamflow in the Mendenhall River Basin.

This data release provides the source data and results of a flood frequency analysis and annual exceedance probability estimation for a flood that occurred on June 22, 2020 in the Fortymile River Basin, Alaska. Data are provided for two streamgages that had at least 10 years of peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .JPEG files), flood frequency parameters, flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities, and annual exceedance probability estimates for the flood of interest. These data were intended to support investigations of streamflow in the Fortymile River Basin.

This data release provides the source data and results of a flood frequency analysis and annual exceedance probability estimation for a flood that occurred on June 22, 2020 in the Fortymile River Basin, Alaska. Data are provided for two streamgages that had at least 10 years of peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .JPEG files), flood frequency parameters, flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities, and annual exceedance probability estimates for the flood of interest. These data were intended to support investigations of streamflow in the Fortymile River Basin.

This data release contains input data and results for an investigation of special conditions for peak streamflow and extreme floods for USGS streamgages in Alaska. Special conditions can include data-collection conditions, basin conditions, flood-generating mechanisms, or other information and can be critical for informing hydrologic analyses such as flood frequency analysis. The dataset contains three tables: (1) table of peak flows identified as extreme floods in Alaska through water year 2022, selected associated special conditions and climate information, and results of an assessment of flood-generating mechanisms, (2) a table of atmospheric river presence or absence data for Alaska for 1980-2019 that were used to assess peak-flow conditions, and (3) a table of input data and results for a drainage area-precipitation cluster analysis for 455 streamgages in Alaska.

This data release provides the source data and results of a flood frequency analysis and annual exceedance probability estimation for a flood that occurred on July 11, 2022 in the Delta River Basin, Alaska. Data are provided for two streamgages that had at least 10 years of peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .JPEG files), flood frequency parameters, flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities, and annual exceedance probability estimates for the flood of interest. These data were intended to support investigations of streamflow in the Delta River Basin.

This data release provides the source data and results of a flood frequency analysis and annual exceedance probability estimation for a flood that occurred on July 11, 2022 in the Delta River Basin, Alaska. Data are provided for two streamgages that had at least 10 years of peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .JPEG files), flood frequency parameters, flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities, and annual exceedance probability estimates for the flood of interest. These data were intended to support investigations of streamflow in the Delta River Basin.

This data release provides the source data and results of a flood frequency analysis for a streamgage in the Hulahula River Basin, Alaska. Data are provided for one streamgage that had at least 10 years of peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .JPEG files), flood frequency parameters, flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities. These data were intended to support investigations of streamflow in the Hulahula River Basin.

This data release provides the source data and results of a flood frequency analysis for a streamgage in the Hulahula River Basin, Alaska. Data are provided for one streamgage that had at least 10 years of peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .JPEG files), flood frequency parameters, flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities. These data were intended to support investigations of streamflow in the Hulahula River Basin.

This data set contains selected information about U.S. Geological Survey (USGS) streamgages in Alaska that had at least 5 years of daily streamflow record through September 30, 2017. The goals for developing this dataset were to identify USGS streamgages that had at least 5 years of daily streamflow that responded mostly to seasonal meteorological inputs, that had a definable drainage basin above a minimum size from which basin characteristics could be determined, and that provided streamflow data not similar to another streamgage record in the dataset. Streamgages meeting these criteria for at least part of their records constituted the dataset for a study investigating seasonal flow regimes and streamflow drivers for Alaska. For 253 streamgages meeting selection criteria, data include period of record characteristics, basin characteristics, and flow regime cluster analysis results. The basin characteristics are provided in their original U.S. customary units and as values transformed to metric units. For an additional 78 streamgages, data include the special conditions affecting streamflow that disqualified the streamgage from the study, including recurring outburst floods, regulation, urbanization, hydrologic redundancy with another streamgage, drainage basin below minimum size, or an indeterminate drainage basin.