SPM 05-30-2021: Heavy Rain, Flooding Along Arkansas River in Southeast Colorado

Issue Date: Sunday, May 30, 2021
Issue Time: 10:00 am MDT

Summary

Saturday was an active day for severe thunderstorms up and down the Eastern Plains, the Front Range Mountains, Palmer Ridge, and Raton Ridge. Storms began to form over the higher elevations in the early afternoon and made their way eastward, producing very heavy rain and large hail. For rainfall estimates in your area, check out our State Precipitation Map the bottom of this post.

Flash flood and flood warnings were issued for several storm cells that produced heavy rain, including for the Cameron Peak burn scar in Larimer County and the Junkins burn scar in Custer County. No flooding was reported over these burn scars yesterday.

However, heavy precipitation continued well into the night last night, resulting in the Purgatoire River near Las Animas to reach minor flood stage (seen in the first hydrograph below). Additional flood reports from upstream near La Junta in the very early hours of the morning include high water flowing across State Highway 109, several homes flooded, and arroyos draining into the Arkansas River causing that river to also reach minor flood stage overnight, eventually cresting at 12.73 feet before coming back down below flood levels (second hydrograph below).

Click Here For Map Overview

The map below shows radar-estimated, rainfall gage-adjusted Quantitative Precipitation Estimates (QPE) across Colorado. The map is updated daily during the operational season (May 1 – Sep 30) by 11AM. The following six layers are currently available: 24-hour, 48-hour and 72-hour total precipitation, as well as maximum 1-hour, 2-hour and 6-hour precipitation over the past 24 hour period (to estimate where flash flooding may have occurred). The accumulation ending time is 7AM of the date shown in the bottom right corner. Also shown optionally are vulnerable fire burn areas (post 2012), which are updated throughout the season to include new, vulnerable burn areas. The home button in the top left corner resets the map to the original zoom.

Note: The 24-hour, 48-hour and 72-hour total precipitation do not contain bias corrections today due to errors in the CoCoRaHS data. This means there may be underestimations in QPE over the southwest and southeast corners of the state.