Lightning, flash floods, and damaging microburst winds are weather hazards that occur regularly within New Mexico during the thunderstorm season which peaks June through September.  Nearly all counties in New Mexico have reported damaging flash floods as well as fatalities and injuries from drowning and lightning. 

Rocky and often steep terrain set the stage for rapid storm water runoff across the state.  Thunderstorms in July and August are capable of producing heavy downpours in short periods of time once the supply of tropical moisture from the Pacific Ocean and from the Gulf of Mexico reaches its peak around the Fourth of July through Labor Day.  Rainfall rates of several inches per hour will be common and thunderstorms tend to be slow moving so heavy rain is dumped on a small area where rainfall rates are very high in a short period of time.

Storm water runoff from burnt areas following large wildfires can be many times greater than normal, so even light amounts of rain of only one-half inch can create damaging and deadly mud and debris slides and unusual heavy flash floods that sweep into nearby neighborhoods and over adjoining roads. 

Our frequency of thunderstorms from June through early September is at its peak at the same time so people are enjoying the outdoors.  Few people realize that the frequency of summertime lightning in areas of New Mexico actually rivals the conditions found in Florida. 

Early and late season thunderstorms generally have less moisture available so rainfall is less intense.  People tend not to seek shelter until they get wet, so if they wait too long before moving indoors then they are at a greater risk of being struck by those first several lightning bolts. 

During the early stages of a thunderstorm, lightning is possible before the rain.  In addition, lightning may arc out of the side of the thunderstorm striking people who otherwise thought they were safe.

After distant heavy rain, arroyos and creeks downstream from the actual rain area will carry the storm water runoff for many hours, creating a special danger at low water road crossings where people are not expecting a water problem.  Also, it becomes very hard to detect flooded low water crossings after sunset.

Several factors create prime conditions for strong down draft winds or dry microbursts near New Mexico thunderstorms.  Storms during early and late season tend to be drier with less rain reaching the ground.  Storms in New Mexico are also high based at 8000 to 12000 feet above ground level.  Evaporative cooling of the light rain shaft helps intensify the microburst or down draft winds which often produce gusts of 45 to 60 mph near the storm.

Summertime thunderstorms especially those across Central and Western New Mexico frequently produce copious amounts of small hail between 1/4 and 1/2 inch in diameter that collects to a depth of 2 to 4 inches on the ground. While the hail size has be 3/4 inch diameter or larger to be considered a severe thunderstorm, the depth of small hail can create temporary dangerous driving conditions along the interstates and highways.  Such copious hail often moves down hill to fill arroyos and road ditches.  An arroyo filled to nearly 12 feet with small during a thunderstorm east of Springer, New Mexico in June 2003. 

To reduce your chances of becoming a victim follow these simple safety rules:

• Check the weather forecast before leaving for extended periods of time.
• Be alert to dark based or threatening clouds moving into your area. Many injuries are produced by the first few lightning strikes.
• If a thunderstorm is approaching, keep a NOAA Weather Radio or AM/FM radio with you.
• Postpone outdoor activities if thunderstorms are imminent. This is your best way to avoid being caught in a dangerous situation.
• Plan your outdoor activities to avoid the peak daily periods of thunderstorms, normally the mid and late afternoon hours.
• The simplest rule...if you hear thunder, you should consider yourself at risk.  Lightning can strike up to 10 miles away from the storm. Go to safe shelter immediately!
• When possible move to a sturdy building or hard top car until the storm has passed.  Avoid small sheds and isolated trees.  
• If boating or swimming, get out and away from water and take shelter.
• If caught outdoors and no shelter is available:  Find a low spot away from trees, fences, and poles.
• If you feel your hair standing on end, lightning may be about to strike. Immediately drop to your knees bending forward with your hands on your head. Only the balls of your feet should be touching the ground.
• Learn first aid and CPR, lightning strike victims are often rendered unconscious and may stop breathing. These victims can often be resuscitated by CPR.

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