Why Worry about Storms When Hammock Camping?
Did you know that United States is one of the most severe weather prone country’s in the world. Each year, people cope with an average of 10,000 thunderstorms, 5,000 floods, 1,200 tornadoes, and two landfalling hurricanes. Approximately 90% of all presidentially declared disasters are weather-related.
Severe weather effects are felt by many of us during our lifetimes and even more prevalent when hammock camping to understand changing weather conditions when being exposed to changing conditions camping or hiking.
To obtain critical weather information, the National Weather Service of the U.S. Department of Commerce’s National Oceanic and Atmospheric Administration, and cooperating organizations, have established SKYWARN Spotter Networks.
Knowing what to observe when camping with changing weather conditions can be a life saver, you can recognize severe weather, develop a plan, and be ready to act when threatening weather approaches. Remember, your safety, and the safety of those in your care, is up to you!
Definitions and Terminology
Severe localized storms occur across all of the continental United States throughout an average year. When camping or hiking you should be aware of storm definitions and terminology used by the National Weather Service in case of emergencies.
Watch: Conditions are favorable for the severe weather event in or near the watch area. Watches are issued for tornadoes, severe thunderstorms, and flash floods.
Warning: The severe weather event is imminent or occurring in the warned area. Warnings are issued for tornadoes, severe thunderstorms, flash floods, and river flooding.
Severe Thunderstorm: A storm that produces hail 3/4 inch in diameter or larger and/or wind gusts of 58 mph or more.
Tornado: Violently rotating column of air attached to a thunderstorm and in contact with the ground.
Funnel Cloud: Rotating, funnel-shaped cloud extending downward from a thunderstorm base.
Downburst: Strong downdraft with an outrush of damaging wind on or near the ground.
Flash Flood: Rapid rise in water, usually within 12 hours of a period of heavy rain or other causative agent (i.e, dam break).
Why Worry About Thunderstorms?
Causes an average of 55-60 fatalities and 400 injuries each year.
Occurs with all thunderstorms.
Cause an average of 60-65 fatalities and 1,500 injuries each year.
Can produce wind speeds in excess of 200 mph.
Can be 1 mile wide and stay on the ground over 50 miles.
Can exceed 125 mph.
Can cause destruction equal to a tornado.
What Are Thunderstorms?
As I’m sure we all have experienced thunderstorms, and we know they can be severe, generally they affect a relatively small areas, however these can be dangerous when hammock camping or hiking and have a severe impact.
Hikers and campers should always be prepared and have additional supplies in your packs just for emergences if you are caught in a storm. If visibility is poor and you are caught out in a storm and unsure of the trail, “when in doubt, sit it out”.
The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Despite their small size, all thunderstorms are dangerous! Of the estimated 100,000 thunder-storms that occur each year in the United States, about 10 percent are classified as severe.
What Are Thunderstorms and What Causes Them?
Every Thunderstorm Needs
Moisture to form clouds and rain.
Unstable air warm air that can rise rapidly.
Lift caused by cold or warm fronts, sea breezes, mountains, or the sun’s heat.
Flash-floods and Floods
Are the number 1 cause of deaths associated with thunderstorms, more than 90 fatalities each year.
Flash-flood occurs within a few hours (usually less than 6 hours) of heavy or excessive rainfall, a dam or levee failure, or the sudden release of water impounded by an ice jam.
A flood is the inundation of a normally dry area caused by abnormal high-water flow. Floods develop more slowly than flash floods, normally greater than 6 hours.
More than half of all flood-related drownings occur when a vehicle is driven into hazardous flood water.
Many flash flood fatalities occur at night.
Six inches of fast-moving water can knock you off your feet.
Two feet of rushing water can carry away most vehicles, including SUVs and pickups.
TURN AROUND, DON’T DROWN!
What Causes Lightning?
Rising air in a thunderstorm cloud causes various types of frozen precipitation to form within the cloud. Included in these precipitation types are very small ice crystals and much larger pellets of snow and ice. The smaller ice crystals are carried upward toward the top of the clouds by the rising air while the heavier and denser pellets are either suspended by the rising air or start falling toward the ground.
Collisions occur between the ice crystals and the pellets, and these collisions serve as the charging mechanism of the thunderstorm. The small ice crystals become positively charged while the pellets become negatively charged.
As a result, the top of the cloud becomes positively charged and the middle to lower part of the storm becomes negatively charged. At the same time, the ground underneath the cloud become charged oppositely of the charges directly overhead.
What are the Physics to Lighting?
When the charge difference between the ground and the cloud becomes too large, a conductive channel of air develops between the cloud and the ground, and a small amount of charge (step leader) starts moving toward the ground.
When it nears the ground, an upward leader of opposite charge connects with the step leader. At the instant this connection is made, a powerful discharge occurs between the cloud and the ground. We see this discharge as a bright visible flash of lightning.
For more information on lightning safety visit: www.lightningsafety.noaa.gov
There is no safe place outdoors when a thunderstorm is nearby.
The vast majority of lightning fatalities happen when seeking shelter during a storm.
More than 80% of lightning fatality victims are male, typically between the ages of 15 and 40.
Lightning fatalities are most common during summer afternoons and evenings.
The energy from one lightning flash could light a 100-watt light bulb for more than 3 months.
Many wildfires in the western United States and Alaska are ignited by lightning.
The channel of air through which lightning passes can be heated to 50,000°F hotter than the surface of the sun! The rapid heating and cooling of the air near the lightning channel causes a shock wave that results in the sound we know as “thunder.”
How Far Away Is the Lightning?
Count the number of seconds between a flash of lightning and the sound of the resulting thunder.
Divide this number by 5 to get an estimate of the distance in miles to the lightning strike.
If you are outdoors and can hear thunder, you are in danger of being struck by lightning.
Although tornadoes occur in many parts of the world, they are found most frequently in the United States.
Tornado intensities are classified by the Fujita Damage Scale developed by Dr. T. Theodore Fujita, a renowned severe weather researcher. The scale ranges from F0-F5, with F5 storms creating incredible damage. The NWS also uses a broader, three-level classification scale, consisting of “weak” (F0-F1), “strong” (F2-F3), and “violent” (F4-F5).
Many strong and violent tornadoes develop as multiple vortex tornadoes. They consist of one large circulation (vortex) with several smaller circulations rotating around it. The smaller vortices usually are responsible for the extreme winds and damage associated with violent tornadoes.
A tornado is a violently rotating column of air extending from a cumuliform cloud, such as a thunderstorm, to the ground.
Tornadoes may appear nearly transparent until dust and debris are picked up or a cloud forms within the funnel.
The average tornado moves from southwest to northeast, but tornadoes can move in any direction and can suddenly change their direction of motion.
The average forward speed of a tornado is 30 mph but may vary from nearly stationary to 70 mph.
The strongest tornadoes have rotating winds of more than 200 mph.
Tornadoes can accompany tropical storms and hurricanes as they move onto land.
Waterspouts are tornadoes that form over warm water. Water spouts can move onshore and cause damage to coastal areas.
Be Ready Year Round
The Enhanced Fujita Scale
The National Weather Service (NWS) uses the EF-Scale to assign a tornado a ‘rating’ based on estimated wind speeds and related damage.
|EF RATING||3 Second Wind Gust (mph)|
How Tornadoes Form?
Before thunderstorms develop, winds change direction and increase in speed with altitude. This creates an invisible, horizontal spinning effect in the lower atmosphere.
Rising air within the thunderstorm updraft tilts the rotating air from horizontal to vertical.
An area of rotation, 2-6 miles wide, now extends through much of the storm. Most tornadoes form within this area of strong rotation.
88% of all tornadoes
Less than 5% of tornado deaths
Lifetime 1 – 10+ minutes
Winds less than 110 mph
Produces EF0 or EF1 damage
11% of all tornadoes
Nearly 30% of all tornado deaths
May last 20 minutes or longer
Winds 111-165 mph
Produces EF2 or EF3 damage
Less than 1% of all tornadoes
70% of all tornado deaths
Can exceed 1 hour
Winds greater than 166 mph
Produces EF4 or EF5 damage
Straight line winds can exceed 125 mph.
A downburst is a small area of rapidly descending air beneath a thunderstorm.
A downburst can cause damage equivalent to a strong tornado.
A “dry microburst” is a downburst that occurs with little or no rain.
Straight line winds are most common in the western United States.
It’s up to you!
Each year, there are many fatalities or seriously injured by tornadoes and severe thunderstorms despite advance warning. Some did not hear the warning; others heard the warning but did not believe it would happen to them. If you hear a warning or observe threatening skies, only you can make the decision to seek safety.
Factual information and images resourced from the National Weather Service