July's monsoon drenched mountains, border region

Rains are spotty elsewhere; Tucson is 15% over normal
2013-08-01T00:00:00Z 2014-07-22T11:14:52Z July's monsoon drenched mountains, border regionTom Beal Arizona Daily Star Arizona Daily Star
August 01, 2013 12:00 am  • 

It was a productive July for monsoon rains in Southern Arizona, particularly atop our mountains and along our southern border.

Douglas, on the international border with Mexico, recorded its wettest month ever, and storms dumped more than 6 inches of rain in a single day along the upper San Pedro River just north of Mexico.

Mount Lemmon recorded nearly a foot of rain - one third of its normal annual total.

The official gauge at Tucson International Airport collected about 15 percent more rain than normal - 2.6 inches - but many parts of town received less.

If you've had a disappointing monsoon so far, it could be it was just too wet to rain at your house, according to weather researchers.

For much of July the atmosphere was sopped, said Mike Leuthold, of the University of Arizona's Institute for Atmospheric Physics.

If you could wring it out, you'd get 2 inches or better each day, but clouds built early and shaded the ground, impeding the heating that gives our thunderstorms their convective pop.

Storms developed over the mountains, but the steering winds were weak and the clouds stayed there, soaking the Catalinas and Rincons and blessing some nearby areas with rain. The far southeast, around Vail and Colossal Cave, was the big winner in the valley, with 3.5 to 5 inches of rain, according to the UA's Rainlog.org

Much of that came in a big storm on July 5 that caused flooding in the Vail/Rita Ranch area.

Sahuarita and Elephant Butte, south of Tucson, also received up to 5 inches in July, with slightly lower totals in nearby Green Valley.

The big totals were farther south, especially in Cochise County, where an area that had been in severe drought got up to foot of rain.

Douglas' 10.23 inches was more than three times its normal 3.15 inches for July, according to the National Weather Service, which also recorded a doubling of Hereford's normal total with 8.09 inches.

Rainlog.org recorded even more dramatic totals around Hereford, where one weather watcher recorded 6.86 inches in a single day.

Rainlog coordinator Gary Woodard said he didn't believe it at first, but the gauge was checked and verified with readings nearby. At one point during that July 9 storm, rain fell at a rate of 12 inches per hour, "which is insane," Woodard said.

It caused "amazing flow rates" in the San Pedro River, he said.

Bridges and crossings of the San Pedro and its tributaries were scoured of silt that had built up over years of slow flows, said Ron Ellis, operations manager for Cochise County's Highway and Floodplain Department.

July has been a busy month for road closures and cleanup, said Ellis, though surprisingly there have been no major flooding events. "We're just trying to keep the roads open till the monsoons are over, and then we'll put the roads back together."

Atop Mount Lemmon, the productive monsoon has filled and overflowed some culverts but caused no major damage, said Mike Stanley, manager of the Mount Lemmon Water District. Stanley said the rain has fallen consistently in a series of storms, with only one real "gully-washer."

Rain was badly needed in Southern Arizona, said Mike Crimmins of the UA's climate assessment group, CLIMAS. "The summer rain is really critical for the rangelands, but keep in mind that we can't ease drought conditions that have developed over the last couple of years with one season."

Crimmins said he lives in "a hole in the middle of town" where little rain has fallen. "That's just the nature of the monsoon," he said. "I don't think it's broken or there's anything wrong with it."

J.J. Brost, science officer for the National Weather Service in Tucson, said such things are indeed normal.

Tucson has been on the southern edge of things for most of the month. "You go from the airport south and the totals are quite significant," he said.

August begins with a good chance of rain through the weekend, with a wetter-than-average month favored by the National Climate Prediction Center.

On StarNet: Get weather information when there is storm activity with StarNet's monsoon live blog at live.azstarnet.com and send your experiences and photos via Twitter and Instagram using the hashtag #tucsonmonsoon

Contact reporter Tom Beal at tbeal@azstarnet.com or 573-4158.

Copyright 2014 Arizona Daily Star. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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