Monday, July 9, 2012

Arizona's Monsoon Season

July 2, 2012 © Thomas J. Kollenborn. All Rights Reserved.

(Image coming soon.)

According to legend and myth the great “Thunder God” roars during the summer months in Arizona. Many of us do not find this hard to believe if we have experienced a severe and violent desert thunderstorm during the summer monsoon season. The lightning, thunder and winds will convince the nonbeliever these storms can be dangerous and violent.

During the summer months most of the storms over central Arizona and the eastern portion of the Superstition Wilderness Area result from warm moist air flowing in from the Gulf of Mexico and sometimes from the Sea of Cortez (also known as the Gulf of California). As this air mass moves across Texas, New Mexico and Mexico it is dried out some. Mountains force the warm moist air upward forming clouds that eventually release their moisture as they rise. This is known as “orographic life.”

These massive anvil-shaped thunderhead clouds that form over Superstition Mountain from July to September normally combine both orographic lift and convectional activity together. Convectional storm clouds result from the rapidly rising and expanding warm moist air and the rapidly falling cold moist air. It is during this convectional activity that lightning is generated. The uneven heating of the earth’s surface causes convectional activity in the atmosphere.

Lightning can be caused by the attraction of unlike electrical charges within a large storm cell. The rapid movement of ice and water molecules, going up and down in a  thunderhead cell, creates friction that results in enormous amounts of static electricity being produced. A single lightning discharge can produce about 30 million volts at 125,000 amperes. A discharge can occur in less than 1/10 of a second. The results of a lightning strike can be horrific.

The rapid rising and falling of warm and cold moist air also creates violent bursts of energy. This type of storm activity can result in microburst. Microbursts can develop winds that momentarily reach up to 200 mph. As the clouds build and combine they form massive anvil-shaped thunderheads called Cumulonimbus clouds. These clouds are massive static generators dispersing lightning and creating violent  winds. These summer storms can be extremely dangerous and violent.

It is these giant thunderheads that dominate the sky above Superstition Mountain during the monsoon season and the lightning produced by these storms over Superstition Mountain can be spectacular.

According to most sources, the safest place during a lightning storm is in a nongrounded automobile. Don’t make yourself part of a lightning rod during an electrical storm by standing by a lone tree or on a high point. The use of your telephone during an electrical storm could be your last conversation, depending on the circumstances of a lightning strike. The same is true when connecting to the Internet.

Standing near or in a swimming pool is asking to meet your maker sooner then you expect. Boating on a lake during an electrical storm is certainly risky behavior on your part. This kind of activity could certainly reduce your chance of living to an older age. Common sense needs to prevail during severe thunder and lightning storms.

Most Arizona monsoons storms are associated with two other dangerous conditions. They are flash floods and dust storms. A thunderstorm can dump three to ten inches of rain over a small area in an hour and create a massive flash flood. A flash flood near Payson, Arizona in the 1970s claimed the lives of 22 campers along Christopher Creek. Many years ago I witnessed a 4-foot wall of water roaring down Queen Creek claiming trucks, horse trailers and horses. This flash flood result from a thunderstorm in the mountains and nobody saw it coming.

Huge dust clouds are often associated with Monsoons storms in the desert. Local weather reporters often refer to our dust storms as “Haboobs.” Egyptian dust storms that blow in from the deserts of North Africa are known as Haboobs.

Dust storms are extremely dangerous to vehicular traffic. Extreme caution should be taken when dust storms are encountered. It is recommended that motorist pull as far off the highway as possible and turn off your lights. While waiting a dust storm to blow over don’t rest your foot on the brake pedal. Your taillights or brake lights might attract drivers in the storm who might think they are following you.

If you’ve ever witnessed a violent electrical storm over Superstition Mountain, it is not difficult to see why the early Native Americans held the mountain in such awe. We can partially explain the phenomena today with modern science, but the early Native Americans could only look to their religious shaman for an explanation.

It certainly was their “Thunder God” with all it fury. We as late arrivals should also respect the awesome power of their “Thunder God.”