June 15 – September 30 · Southeast Arizona

The Sierra Vista monsoon car guide

Rule one: never drive into a running wash

The washes that cross roads all over Cochise County — along SR-90, SR-92, Charleston Road, Moson Road, and half the dirt roads toward the San Pedro — are dry 350 days a year and lethal the other fifteen. Six inches of moving water can stall a car; a foot or two can float and carry one. Arizona backs the common sense with law: under A.R.S. 28-910, widely known as the Stupid Motorist Law, a driver who goes around barricades into a flooded crossing can be billed for their own rescue. The barricade is not a suggestion. Turn around; the wash usually drops within hours of the storm passing.

Rule two: in blowing dust, pull aside and go dark

Monsoon outflows kick up dust walls with near-zero visibility, especially on the open stretches of SR-90 toward Whetstone and SR-80 toward Tombstone. ADOT's guidance is Pull Aside, Stay Alive: get fully off the pavement, stop, and turn off every light — headlights, hazards, brake lights. Drivers in a brown-out steer toward the lights ahead of them; if yours are on while you're parked, you're the target. Wait it out; dust channels typically pass in minutes.

Why breakdowns spike in storm season

Every monsoon, the same three failures fill the phone line in Sierra Vista:

The pre-monsoon 20-minute check

Before the first big storm each summer, five things earn their keep: battery load test (storm season stresses weak batteries — see battery service), wiper blades front and rear, tire tread depth (bald tires hydroplane on the first wet Fry Boulevard afternoon of July), brake condition for wet-road stopping distances (brake inspection), and headlight function for the mid-afternoon dark of a big cell. All five are checked in one mobile visit at your home or workplace.

If a storm already got you

Car soaked, hydro-locked, or stranded past a wash? Don't crank an engine that may have taken in water — repeated cranking turns a drying-out problem into a bent-rod problem. Call, describe what happened and where the water reached, and get an honest read on whether it needs a driveway visit, a dry-out, or genuinely a tow. Storm damage is exactly the situation where fixing it where it sits beats dragging it 75 miles to find out.