The summer of 2013 was drier than normal along the Front Range, so when rain started falling on the northern end on September 9, 2013, some greeted it with enthusiasm. Others tempered their enthusiasm when the five-day forecast revealed an anomalous lineup of raincloud icons. In fact, a stationary low pressure system had developed over the Great Basin, to the west of the Rocky Mountains, and began to pull monsoonal tropical moisture from the Pacific Ocean as well as more moist air off the Gulf of Mexico. This circulation pattern directed and focused these moisture plumes toward the Front Range. The rain showers beginning on September 9th didn’t let up until September 15th, falling most intensely between September 11th and 13th, 2013. According to the Colorado Climate Center, total rainfall for the week beginning Monday, September 9th measured 16.9” in Boulder, 9.3” in Estes Park, 5.9” in Loveland, and 6.0” in Fort Collins. Because the steep, rocky terrain in and around these communities channels water, the effects of precipitation can be greatly amplified and lead to rapid runoff. The sudden, huge influx led to extensive flooding that damaged infrastructure on the Arapaho and Roosevelt National Forests and devastated property, infrastructure, and lives in surrounding communities.