Staying Safe in Arizona Monsoon Season

August 07, 2017

arizona monsoon seasonIf you’re not an Arizona native, you probably assume this state is one of the driest. It’s full of saguaro cactus, cow skulls and tumbleweeds, right? (You learned that from watching cartoons.)

You’re correct — Arizona ranks in the bottom five states for average annual precipitation. However, Arizona also experiences a weather phenomenon called the monsoon, in which storms can dump more water than you’ve ever seen. Here’s what you need to know if you’re in the state during Arizona monsoon season.

What is the Arizona Monsoon Season?

Most people think a monsoon means a heavy rainstorm, but it’s actually something bigger than that. A monsoon is a seasonal shift in the prevailing winds that dramatically changes the weather. Although monsoons are typical in southeast Asia, other parts of the world experience them too, including Arizona, New Mexico, and areas of Utah and Colorado.

In Arizona, monsoon season means that the dry winds blowing from the west are replaced by southeasterly winds that carry moisture from the Gulfs of Mexico and California. Water vapor in the warm, moist air forms clouds as it rises, then freezes into ice crystals, which fall and become rain. The result: strong, sudden storms.

One storm begets another, as meteorologist Austin Jamison tells AZCentral: “You tend to have a generational effect where storms will pop up over the mountains, then outflow air coming out of those storms kicks off new, child storms further away from the initial formation area.” This makes Arizona monsoon storms hard to predict.

When is Monsoon Season in Arizona?

For many years, meteorologists defined monsoon season as beginning when Arizona saw three consecutive days when the average dewpoint temperature — the temperature at which water vapor begins to condense — was 55 degrees or higher. But in 2008, the National Weather Service simplified things. The official monsoon season in Arizona now lasts from June 15 to September 30.

The severity of the Arizona monsoon season varies dramatically, however. The driest on record was in 1924, when hardly any rain — about a third of an inch — fell. The wettest year was 1984, which saw a total of 9.56 inches of rain. Flagstaff typically gets the most rain, followed by Phoenix and Tucson.

What are the Dangers of a Monsoon?

Monsoon storms are an essential part of the ecosystem. The storms bring much-needed rain to Arizona and other parts of the American Southwest. But monsoon season can also be dangerous — even deadly — if you’re caught out in a storm. Perils include:flash flood safety

  • Dust storms: Often, the first sign of a monsoon storm is a huge wall of dust, known as a haboob. These look apocalyptic, as you can see in this time-lapse video.
  • High winds: Strong winds can also be a threat, especially if you’re driving. Stay well away from any fallen power lines you see, because the electricity can travel through the ground.
  • Flash floods: Because heavy downpours are rare in Arizona, the ground — and the street drains — can’t handle huge volumes of water. This means a monsoon storm may rapidly be followed by floods in roadways, gullies, or any low-lying ground.
  • Lightning: If you hear thunder, take shelter in a hard-roofed vehicle or a building — not under a tree.
  • Hail: Monsoon thunderstorms may pelt you with hail. There’s not much you can do but find cover for yourself and your vehicle.

How can you stay safe in monsoon season?

The first, and simplest, rule is to stay off the roads if a storm is predicted. If you’re already traveling when a monsoon storm hits, it’s wise to pull over or take it slow. When visibility is zero due to a dust storm, there’s no point in trying to drive. The best course of action, according to the Arizona Emergency Information Network, is to pull off the road, turn off your headlights and taillights, put your vehicle in park and take your foot off the brake, so your brake lights are not illuminated. Why? “Other motorists may tend to follow taillights in an attempt to get through the dust storm, and may strike your vehicle from behind.”

The biggest threat to drivers is flooding. “Flash flooding is responsible for more fatalities — 40 in Arizona since 1996 — than any other thunderstorm-associated hazard,” the emergency network says. It only takes six inches of water to flood most cars or to knock you off your feet. As little as 10 inches of water can carry away passenger vehicles, including SUVs. The first rule of flash flood safety: If you see a sign or barrier warning you about flood danger, turn around. And if your car does get caught in a flash flood, get out and get to higher ground, if you can.

Arizona monsoon season and your auto insurance

Arizona car insurance minimums are $15,000 a person, $30,000 per accident for bodily injury and $10,000 per accent for property damage. However, comprehensive coverage can pay for damage caused by hail or floods. After the storm, report any vehicle damage to your car insurance company.

If you don’t have comprehensive insurance, then it might be time to shop around for a new policy. We compared auto insurance prices in Arizona, and found one woman’s monthly premium ranged from $47 to $117. That’s a big difference!

Compare.com makes it easy to compare your own car insurance prices. Enter your info and get multiple free quotes today.

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Based on a survey of 100 California Residents. Average savings determined via a comparison of their selected policy against their self-reported annual premium.