Colorado State University
Real-Time Weather Data
Precip. Sys. Research Group
Colorado State University
Real-Time Weather Data
Precip. Sys. Research Group
Colorado State University
Real-Time Weather Data
Precipitation Systems Research Group
Skip navigation
  • Home
  • CSU WRF Forecasts
    • 12-km Ensemble: CO
    • 12-km Forecast Soundings
    • 4-km Forecast
    • 4-km Forecast: WxC Zoom
    • 4-km Forecast Soundings
    • 12-km Model Information
    • 4-km Model Information
  • CSU Machine Learning Forecasts
    • CSU-MLP (precip)
    • CSU-MLP (severe weather)
    • downslope windstorms
  • Model Forecasts
    • GFS
    • NAM
    • GEFS
    • NAM 3-km Nest
    • HRRR
    • ECMWF
    • AIWeather
  • Heavy Precip
    • ARI Monitoring
    • TORFF Identification
  • Links
    • Fort Collins Weather Station
    • Christman Field Wx Station
    • CoAgMET
    • NWS Denver/Boulder
    • NWS Cheyenne
    • CIRA SLIDER satellite imagery
    • Fort Collins Rain Gauges

Monitoring of heavy precipitation events

These images show locations where average recurrence intervals for precipitation have been exceeded. These are referred to, for example, as "100-year rainstorms", though this terminology can cause confusion, so a more accurate description is "less than a 1% probability of occurring at a given location in any given year." This is an automated search for the types of events discussed in Schumacher and Johnson (2005, 2006) and Stevenson and Schumacher (2014), using gridded precipitation analyses, as well as updated to use NOAA's Atlas 14 to define the average recurrence intervals. (In the states of Washington and Oregon, Atlas 14 has not yet been updated, so no points are shown.) Archived images from past events when the thresholds have been exceeded are shown below.

Each dataset has been regridded to a 4-km latitude-longitude grid (the same grid used by the PRISM Climate Group) prior to calculating the exceedance points. This allows for a closer "apples-to-apples" comparison between precipitation datasets. The archive of past events is actively under development; if you don't yet see images for a particular dataset/duration, check back soon! Recent data (e.g., within the current year) has not undergone quality control, so use recent maps with caution.


Select dataset: Stage IVMRMSPRISMCONUS404      Current maps  Interactive maps of past events
Select average recurrence interval: 10-year100-year1000-year
Select duration: 72-hour48-hour24-hour6-hour
Select year: 2002200320042005200620072008200920102011201220132014201520162017201820192020202120222023202420252026

Left arrow for previous frame, right arrow for next, space to pause/play; click to open image in new tab. Each event is listed as "mmddhh_e" (2-digit month, 2-digit day, 2-digit hour for end of accumulation period, one digit for the event number on this date).

   
010312_0 010912_0 011212_0 020712_0 020712_3 020812_1 020812_2 020812_3 020912_0 020912_2 021012_0 021312_0 030612_0 031312_0 031412_0 031512_0 031612_1 031712_0 032012_1 032112_1 032112_2 032212_0 040912_0 041012_0 041112_0 042012_0 042112_0 042112_1 042212_1 050112_0 050412_0 051412_0 051512_0 051612_0 051612_1 051712_1 051712_2 051912_0 051912_1 052012_0 052112_0 052112_1 052112_2 052212_1 052212_2 052312_2 052312_3 052412_0 052412_1 052512_0 052512_1 052612_0 052712_0 052712_1 052812_0 052912_1 053012_0 053112_0 053112_2 060512_0 060712_0 060812_0 060912_0 060912_1 060912_2 060912_3 060912_4 060912_5 061012_0 061012_1 061012_2 061012_4 061112_0 061212_0 061212_3 061512_0 061712_0 061812_0 061812_1 061912_2 062012_0 062012_1 062012_2 062012_4 062012_5 062112_2 062112_4 062112_5 062212_0 062212_2 062312_0 062312_2 062312_3 062412_0 062412_1 062612_0 062612_1 062812_0 062812_1 062812_2 062912_0 063012_0 063012_2 063012_3 063012_4 070112_1 070112_2 070112_3 070112_4 070212_0 070212_1 070212_2 070212_3 070312_2 070312_3 070412_2 070512_0 070512_1 070612_0 070612_1 070612_2 070712_0 070712_1 070712_2 070712_3 070812_0 070812_1 070812_3 070912_1 070912_3 070912_4 071012_1 071112_0 071212_1 071412_0 071512_1 071512_3 071612_2 071612_3 071612_4 071712_0 072012_1 072112_0 072112_1 072212_0 072212_2 072212_3 072212_4 072312_2 072412_0 072412_1 072512_0 072512_3 072512_4 072612_1 072612_2 072612_3 072612_4 072712_0 072712_1 072712_2 072712_3 072812_0 072812_1 072812_2 072812_4 072812_5 072912_1 072912_2 073012_3 073012_4 073112_0 073112_1 073112_4 080112_1 080112_3 080112_5 080212_1 080312_0 080412_0 080412_1 080512_0 080512_1 080612_0 080712_1 081012_1 081112_0 081312_0 081412_0 081412_3 081512_0 081512_2 081512_4 081612_0 081612_1 081612_3 081712_1 081812_1 082212_0 082312_0 082412_0 082412_2 082412_3 082412_4 082512_0 082712_1 082812_0 082812_2 082812_3 082912_0 082912_1 082912_2 083012_0 083012_1 083012_2 083112_0 090112_0 090112_1 090112_2 090212_0 090212_1 090312_0 090412_0 090512_0 090512_1 090612_0 090812_1 090912_0 090912_4 091012_1 091012_2 091112_0 091112_2 091212_1 091412_0 091412_1 091512_0 091612_1 091712_0 091812_0 091912_0 092212_1 092312_0 092412_1 093012_0 100312_0 101012_0 101112_0 101212_1 101212_2 101912_0 102012_0 102112_1 102212_0 102312_1 102412_0 102512_0 102912_0 110812_0 110912_0 111012_0 111012_1 111212_0 111212_1 111312_1 111612_0 111612_1 111612_2
on the left is a map showing locations where rainfall exceeding an average recurrence interval threshold occurred, and on the right is the corresponding precipitation analysis for that time period

This material is based upon work supported by the National Science Foundation under Grant No. AGS-2337380. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.



DISCLAIMER: The images and data on this site are intended for meteorological education and research purposes and, although they should generally be up to date, are not monitored at all times. Do not use for making decisions where money or lives are at stake. For official forecasts and warnings, visit the National Weather Service.

Walter Scott, Jr.
College of Engineering
Research Group Home People Research Teaching Resources Contact
Precip. Systems Research Group
GIVE
Contact CSU Equal Opportunity Privacy Statement Disclaimer

© 2026 Colorado State University, Fort Collins, Colorado 80523 USA

© 2026 Colorado State University,
Fort Collins, Colorado 80523 USA

Colorado State University logo