Flash Flood in Washington County, Utah

An extended period of moderate to heavy rainfall occurred in southwest Utah on the morning of September 11th, during which 3.24 inches of rainfall was measured in Ivins, Utah. In nearby Santa Clara, an earthen dike (called the Laub Dike) burst, releasing all of the water in the associated retention pond. This water and mud flowed into nearby homes and businesses, damaging both public infrastructure and private properties. A total of $3.8 million in damage was done to public infrastructure, including damage to the dike, streets, and sidewalks. The flood also damaged 16 businesses and 63 homes; some of these buildings had internal damage due to water and mud flowing into them, while other buildings experienced serious structural damage.

Monsoonal moisture interacted with a strong upper-level low on September 11th, producing heavy rain and flash flooding in many locations across southern Utah. The most significant event of the day was the failure of the Laub Dike in Santa Clara, causing flooding in many area homes and businesses.