A 'Triple Threat' of Moisture Brings Life-Threatening Flooding This Week

A significant flooding event is brewing across the southwestern and central portions of the U.S. as the remnants of two hurricanes from the Pacific join forces with a non-tropical event coming in from the West. Here is a look at who is going to get caught up in the crosshairs of this deluge and when to expect the impacts.

Two Recent Hurricanes Enhancing Rainfall Totals in the Southwest

A triple flooding threat is unfolding across a large swath of the Southwest and beyond this week, coming just days after the region experienced heavy rain. The first round of moisture fired up late Monday as what was once Hurricane Odalys made its way into the Desert Southwest.

The bulk of this storm's remnants are impacting portions of Arizona, New Mexico, southern Utah, and the southwestern corner of Colorado. Falling temperatures in the higher terrain of the interior West could support the development of the season's first snowflakes.

The rain coverage and intensity will increase on Tuesday as what is left of Hurricane Polo, currently over northwestern Mexico, connects with a southward plunge in the jet stream pushing in from the West Coast. While Polo will disintegrate as it moves over the rugged terrain of northern Mexico, the lingering energy and moisture will still be potent enough to amplify rainfall totals in the Southwest and the Plains.

This is shaping up to be a long-lasting rainfall event with the moisture machine persisting through Friday across a large swath of the Southwest, the south-central U.S., and the Plains. Two separate zones within this region are expecting widespread rainfall totals of 4 to 8 inches. Pockets of locally higher amounts are a possibility in areas where thunderstorms and associated rain bands stall.

Residents in the impact zone will want to be prepared for travel disruptions. The extensive drought as of late across much of the southern U.S. means that soil is less permeable. Dry and compacted soil is at an inherently higher risk of rapid runoff during times of heavy rain. Top rainfall rates are forecast to hit 2 to 3 inches per hour during the peak of the activity, laying the groundwork for the potential of life-threatening flooding.