Driven away by drought
Dry conditions affecting animals and humans alike
Friday was the official the start of the North American Monsoon according to the National Weather Service, although Arizona's parched landscape gives no indication of rain in sight and Prescott hasn't seen a drop since April.
Meteorologists and climatologists from the Weather Service and University of Arizona gathered Thursday for a monsoon forecast briefing via the Web.
All of Arizona is in some kind of drought right now, and 83 percent of that drought is severe or worse.
The drought cycle began in 1995 and history indicates the drought trend could last a total of 20-30 years, noted Michael Crimmins, University of Arizona Extension specialist and associate professor.
It would take several wet months in a row to break the trend, he said.
The rare back-to-back La Niña winters haven't helped, but a positive note could be ahead for the Southwest as weather experts see strong signs of an El Niño weather pattern taking hold by late summer here.
The monsoon typically arrives some time around the Fourth of July in Prescott, after moving up from Mexico. Last year's monsoon produced 4.17 inches of rain compared to the 30-year average of 7.96 inches in Prescott. Other communities around Yavapai County also saw below-average monsoon rain.
Experts are seeing signs that the monsoon might arrive a bit early this year.
But forecasting much else about precipitation during the complex monsoon remains a tricky business.
Without any strong indicators, forecasters are predicting equal chances of a wet or dry monsoon, although they generally agree it will be warmer than average.
"There is some indication we might start off with a 'bang' like last year," said John Brost of the National Weather Service office in Tucson, talking about strong early monsoon storms. But that doesn't necessarily translate into a wetter monsoon.
Weather experts are seeing strong signs of an El Niño taking hold by August-October, but that doesn't necessarily translate into a wetter monsoon either, Brost said.
Thursday's briefing, organized by the University of Arizona's Climate Assessment for the Southwest (CLIMAS), also included talks about long-term wildfire impacts, the use of tree ring data to better understand long-term monsoon variability, and U of A work on new, more reliable method of measuring regional soil moisture.
Large-scale wildfires will impact the landscape for centuries, said Don Falk of the U of A School of Natural Resources and the Environment.
"It's not going to come back as the same forest," he said. Brush is replacing the burned trees, instantly changing the landscape, and it's likely to stay that way for a long time.
The annual cost of suppressing U.S. wildfires has risen from about $500 million in 1990 to $1.75 billion in 2010, he said.
If the government invested 10 percent of that annual firefighting money into forest restoration, it could treat more than 1 million acres and employ thousands of people, he said.
Tree ring analysis at the University of Arizona's Tree Ring Lab shows a trend toward dry monsoons following wet winters, and wet monsoons following dry winters, between 1950 and 2000, U of A scientist Daniel Griffin said.
But looking back to the year 1550 through tree ring analysis, this correlation doesn't hold, he said.
The analysis of tree ring formation during the monsoon also pointed out an unusual run of dry monsoons between 1880 and 1905, he said.
A Southwest mega-drought from 1560 to 1595 wasn't as warm as today's drought, and it didn't produce the massive wildfires of today.
"Increasing temperatures really exacerbate drought conditions," he noted.