FloodZoneMap.org

Flash Flood — Union, IA

Sep 19, 2010

A quasi-stationary front was located south of Iowa as an upper level shortwave advanced across the area in strong westerly flow aloft. The atmosphere was somewhat unstable, albeit the instability was elevated in nature. Available CAPE was in the 1000 to 2000 J/kg range with lifted indices of -3 to -5 C. Moisture had pooled over the area with precipitable water values in the 1.3 to 1.7 inch range. The freezing level was quite high for mid September at between 14,000 and 14,500 feet. Signific

Source: NOAA National Weather Service Storm Events Database (event 251235). Narrative written by NWS staff at the time of the event.

Flood Risk Context for Union, IA

This event is one of many recorded floods in Union County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.

View Union County flood data →

More Flood Stories

Flash Flood$10K damage

Union, IA · Jun 25, 2019

During the evening of the 25th, a number of storms were able to initiate along a relatively stationary boundary situated across southern Iowa. On the warm side of the boundary surface conditions were in the mid 80s for temperature and upper 60s to low 70s dewpoints.

Read the full account →
Flash Flood$10K damage

Union, IA · Sep 5, 2018

Wet conditions continued across the state with yet another round of moderate to heavy rainfall on top of already mostly saturated conditions. A shortwave moving through the upper level flow out of the southwest, a surface front situated to the west and northwest of the state,…

Read the full account →
Flash Flood$200K damage

Union, IA · Sep 9, 2014

Deep moisture moved into Iowa as a strong shortwave moved into the central U.S. Moisture from former hurricane Norbert moved into the central U.S. as a low pressure system developed over Kansas.

Read the full account →
Flood$200K damage

Union, IA · Sep 10, 2014

Deep moisture moved into Iowa as a strong shortwave moved into the central U.S. Moisture from former hurricane Norbert moved into the central U.S. as a low pressure system developed over Kansas.

Read the full account →