After flooding rainfall in the Southwest, a break is on the way

Andrew Johnson-Levine
·4 min read
14

The streets in Moab, Utah, turned into a raging river as flash flooding swept through the city over the weekend as equally dramatic footage showed floodwaters rushing through the parched landscape in Arizona. Those were just some of the flooding scenes set into motion by the North American monsoon in recent days and weeks.

AccuWeather meteorologists say that a drier pattern will develop across the Southwest this week ahead of another potential uptick in showers and thunderstorms.

Rainfall will be less frequent and widespread as moisture associated with the North American monsoon drifts toward the east, AccuWeather Meteorologist Thomas Geiger said. That eastward-shifting plume of moisture was the culprit behind flooding rainfall in Texas, including the Dallas area.

Chances for rainfall will be lower across the Southwest overall, AccuWeather forecasters say, but isolated showers and thunderstorms can still occur through the middle of the week. The rainfall will be largely beneficial to the drought-stricken region, but more incidents of flash flooding are possible.

"With how dry the ground tends to be in the Southwest, any rain that falls will not soak in as quickly as it does in wetter areas. Because of this, rainfall amounts that would be quite manageable farther east can lead to more serious problems in these desert climates," Geiger explained.

Forecasters urge people spending time outdoors to avoid dry riverbeds, called arroyos, as they can quickly turn into raging rivers almost instantaneously. One such occurrence was captured on camera by Extreme Meteorologist Reed Timmer, who encountered many flooded roadways near Tucson, Arizona, this past weekend.

The hit-and-miss nature of the rain will persist as is often the case with summer thunderstorms. Conditions across the Phoenix area demonstrate how some places can miss out in rainfall, while other locations just a few miles away can repeatedly see rounds of heavy rain.

Approximately 200 miles east of Phoenix, the small town of Duncan, Arizona was evacuated on Monday, as the nearby Gila River hit a major flooding stage in the morning by rising to over 20 feet of water level.

Despite missing out on some of the recent storms, the Valley of the Sun is on the cusp of a wetter-than-average August with a total of 0.81 of an inch of rain so far this month. In the mountains just to the north, even more precipitation has been recorded. Prescott, Arizona, often one of the state's wettest locations during the monsoon season, has picked up more than 3 inches of rain so far in August, already putting the city above average for the month.

Regardless of exactly where the heaviest rain fell, the storms certainly made their presence known around the Phoenix metro area. In a city known for scorching heat and dry weather, massive flashes of lightning could be seen as storms rolled through late last week.

To the northwest in Las Vegas, heavy rainfall has been a frequent visitor lately. Stunning scenes of flooding were captured in Sin City in recent days and weeks, as area roads turned into rushing torrents of water and popular casinos in the city were inundated by streams of rainwater. So far in August, 0.61 of an inch of rain has fallen in the city, which is almost twice the typical monthly average. That amount of rain is highly abnormal for the desert city and plenty enough to result in flooding.

Any rainfall will help to put a dent in the ongoing drought in the Southwest, but much more is needed as water levels in reservoirs like Lake Mead have reached historic lows. More than 50% of the West was experiencing severe, extreme or exceptional drought as of last Thursday, according to the U.S. Drought Monitor.

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"It will take much more than one event to break the drought, but recent rainfall triggered by the monsoon has been a big step in a positive direction," Geiger said.

Toward the end of the week another increase in moisture could lead to more numerous storms in the Southwest once again, and it will serve as a reminder that the monsoon season is not yet finished.

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