Lightning Safety

NPS

One of the most powerful forces of nature is lightning. It is beautiful to watch, but also extremely dangerous. In the United States, there are about 25 million lightning flashes every year. In Rocky Mountain National Park, lightning flashes are common from June through September. Each lightning flash can potentially cause serious injuries or death. It is important to understand the dangers of thunderstorms and lightning, so that you can get to a safe place.

What is Lightning?

Lightning is a giant spark of electricity in the atmosphere or between the atmosphere and the ground. As lightning initially develops, air acts as an insulator between the positive and negative charges in a cloud and between a cloud and the ground. When the differences in charges becomes too great, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning.

Lightning can occur between opposite charges within a thunderstorm cloud (Intra Cloud Lightning) or between opposite charges in the cloud and on the ground (Cloud-To-Ground Lightning). Cloud-to-ground lightning is divided into two different types of flashes depending on the charge in the cloud where the lightning originates.

How are Thunder and Lightning Connected?

Thunder is the sound made by a flash of lightning. As lightning passes through the air, it heats the air quickly. This causes the air to expand rapidly and creates the sound wave we hear as thunder. During a thunderstorm, you can hear thunder about 10 miles from a lightning strike. Since lightning can strike outward 10 miles from a thunderstorm, if you hear thunder, you are likely within striking distance from the storm.

Below Are Some Tips for What to Do When Recreating During a Thunderstorm

 

Backcountry Lightning Risk Management

National Weather Service

How to Manage Lightning Risk When Recreating in Rocky Mountain National Park

Before heading out on your next Rocky Mountain adventure, know how to protect yourself when thunder roars and lightning strikes. Most importantly, be aware of your surroundings and know the most high-risk places to be compared to the safest locations to be when recreating in the mountains. When it comes to lighting, there are no fully safe options in the outdoors.

If possible, shelter inside a vehicle or a building. If you are out on a hiking trail, the next best option is to get below tree line and shelter at the base of a cluster of low elevation trees or in a lower elevation dry ditch or gully.

What If I am Driving on Trail Ridge or Old Fall River Roads?

If you hear thunder or see lightning when driving on Trail Ridge Road or Old Fall River Road, or if you are standing at an overlook like at Rock Cut or Rainbow Curve, the best thing to do is get back inside your vehicle and shelter there. Do not walk to overlooks or stand in parking areas during a thunderstorm.

What If I am Out in the Park, Not Near My Vehicle?

On a scale of 0 (highest risk - avoid) to 10 (safest as possible), know the most risky places to be compared to the safest places to be during a thunderstorm. Refer to the graphic above labeled "Backcountry Lightning Risk Management."

• 0: At the top of the tallest mountain peak in the area, above treeline
• 1: Near the top of a mountain, above treeline, and located below other nearby peaks.
• 1: On a wide-open slope of a mountain above treeline
• 1: In a cave or rock shelter on the side of a mountain
• 1: On the windward side of a mountain where a storm is coming from
• 1: On open water in a boat, canoe or kayak, or sheltered near trees close to open water
• 1: Inside a cave, rock shelter, or rock outcropping
• 1: Near streams, rivers, wet gullies, and boggy ground
• 2: While descending a mountain in a dry gully or lower-elevation area of the mountain. (A dry gully is a safer place to be compared to open slopes above treeline or the top of a mountain peak).
• 3: In ditches and other lower-elevation places on a route, below treeline.
• 3: Below treeline and sheltered at the base of a cluster of low elevation trees.
• 10 (safest option): Shelter inside a vehicle or a building. If you are near a vehicle or a building and you hear the roar of thunder, head indoors! The safest place you can be is inside a building or a metal-topped vehicle with tires.

When Camping Inside a Tent

When camping inside a tent, keep in mind that a tent has metal poles and could attract lightning.

If camping in a high elevation or exposed area, get out and away from your tent and try to shelter near a grove of trees and assume the lightning position. If camping near a body of water (rivers, lakes, streams, or wet and boggy areas), try to relocate to a dryer areas near a grove of trees. Move away from the body of water.

 

Backcountry Lightning

NPS, NWS and NOAA

What to do If You Cannot Move to a Safer Location?

If you are caught outside during a thunderstorm and cannot get to a safer location, the following steps can help reduce your risk of a lighting strike:

• Immediately get off of elevated areas, such as exposed mountain peaks and slopes.
• DO NOT lie flat on the ground. Minimize the surface area that your body is in contact with the ground.
• Assume the lightning position by crouching down. Take a position that you can stay in for at least 20-30 minutes. If possible, sit or crouch on top of a backpack to reduce your direct contact with the ground. Put your hands behind your head and bend forward.
• Look for and stay away from any objects that could conduct electricity, like tall trees, fences, powerlines, windmills, poles, etc.
• Never use a cliff, cave or rock overhang to shelter from the storm. Lighting can travel through the rock, bounce, and strike you.
• Shelter for at least 30 minutes after you hear the last sound of thunder.