Severe Weather Awareness
Alerts and Warnings
Weather Notification Terms and Services
The National Weather Service uses the words "advisory", "watch" and "warning" to alert you to potentially dangerous weather. Understanding these terms and knowing how to react can be a life saver.
Advisory is issued when a hazardous weather or hydrologic event is occurring, imminent or likely. Advisories are for less serious conditions than warnings that cause significant inconvenience and if caution is not exercised, could lead to situations that may threaten life or property.
Watch means weather conditions are favorable for dangerous weather to occur. In other words, a "watch" means watch out for what the weather could do, and be ready to act accordingly. You may wish to alter or have a back-up plan for any outdoor activities or travel.
Warnings are used for severe thunderstorms, tornadoes and flash floods, a warning means the weather event is imminent or occurring somewhere in the defined warning area and that people need to take shelter as soon as possible.
Weather Radios are one of the best ways to stay tuned-in to dangerous weather. These radios receive broadcasts from the National Weather Service. The broadcasts are from local weather service offices. The stations also broadcast all watches and warnings. Some weather radios have a feature that turn on the radio automatically when a watch or warning is broadcast. Such "tone alert" weather radios are highly recommended for places where large numbers of people could be endangered by tornadoes or flash floods. These include schools, nursing homes, shopping center security offices, hospitals, and recreation areas such as swimming pools.
This National Weather Service page has information on weather radios, including a list of weather radio stations in each state.
Extreme Heat and Notifications
Extreme waves of heat can be life threatening or even deadly. An excessive heat watch or warning is issued when dangerous heat conditions are possible or expected within 72 hours. Advisories are used to warn of dangerous heat conditions prior to onset of the heat event. Read more below about these and other types of heat related notifications.
The National Weather Service issues the following heat-related notifications as conditions warrant (based on the National Oceanic and Atmospheric Administration, NOAA, notification categories):
Excessive Heat Outlook is issued when the potential exists for an excessive heat event in the next 3-7 days. This is used to provide information to those who need considerable lead time to prepare for the event, such as public utility staff, emergency managers and public health officials.
Excessive Heat Watch is issued when conditions are favorable for an excessive heat event in the next 24 to 72 hours. This is used when the risk of a heat wave has increased but its occurrence and timing is still uncertain. An excessive heat watch provides enough lead time so that those who need to prepare can do so, such as cities officials who have excessive heat event mitigation plans.
Excessive Heat Warning is issued within 12 hours of the onset of extremely dangerous heat conditions. These products are issued when an excessive heat event is occurring, is imminent, or has a very high probability of occurring. The warning is used for conditions posing a threat to life. An advisory is for less serious conditions that cause significant discomfort or inconvenience and, if caution is not taken, could lead to a threat to life.
Heat Index, sometimes referred to as the apparent temperature is given in degrees Fahrenheit. The heat index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature. NOAA's heat alert procedures are based mainly on Heat Index values. To find the heat index temperature, look at the heat Index chart. As an example, if the air temperature is 96°F and the relative humidity is 65%, the heat index--how hot it feels--is 121°F. The National Weather Service will initiate alert procedures when the Heat Index is expected to exceed 105°-110°F (depending on local climate) for at least 2 consecutive days.
Heat Disorders occur when the body loses its ability to shed heat through circulation and sweating. Heat-loss efficiency may diminish with age, but sunburn is a factor at any age because it significantly reduces skin's ability to shed heat. When heat gain exceeds heat loss, or when the body can no longer compensate for fluids and salt lost through perspiration, the core temperature of the body begins to rise, and heat-related illness may develop. Heat disorders vary in seriousness, but they share a common cause: in a warm environment, the person has taken exposure or exercise beyond the limits of the body's age and physical condition.
Tips for Preventing Heat-Related Illness
- Drink more fluids (nonalcoholic), regardless of your activity level. Don’t wait until you’re thirsty to drink. Warning: If your doctor generally limits the amount of fluid you drink or has you on water pills, ask how much you should drink while the weather is hot.
- Don’t drink liquids that contain alcohol or large amounts of sugar–these cause you to lose more body fluid. Also, avoid very cold drinks, because they can cause stomach cramps.
- Stay indoors and, if possible, stay in an air-conditioned place. If your home does not have air conditioning, go to the shopping mall or public library–even a few hours spent in air conditioning can help your body stay cooler when you go back into the heat. Call your local health department or Red Cross chapter to see if there are any heat-relief shelters in your area.
- Electric fans may provide comfort, but when the temperature is in the high 90s, fans will not prevent heat-related illness. Taking a cool shower or bath, or moving to an air-conditioned place is a much better way to cool off.
- Wear lightweight, light-colored, loose-fitting clothing.
- NEVER leave anyone in a closed, parked vehicle.
- Although anyone can suffer from heat-related illness, some people are at greater risk than others. Check regularly on: infants and young children, people aged 65 or older, people who have a mental illness, those who are physically ill, especially with heart disease or high blood pressure.
- If you must be out in the heat:
- Limit your outdoor activity to morning and evening hours
- Cut down on exercise. If you must exercise, drink two-to-four glasses of cool, nonalcoholic fluids each hour. A sports beverage can replace the salt and minerals you lose in sweat. Warning: If you are on a low-salt diet, talk with your doctor before drinking a sports beverage. Remember the warning in the first “tip” (above).
- Try to rest often, in shady areas
- Protect yourself from the sun by wearing a wide-brimmed hat (also keeps you cooler) and sunglasses and by putting on sunscreen of SPF 15 or higher (the most effective products say “broad spectrum” or “UVA/UVB protection” on their labels).Visit at-risk adults at least twice a day and watch them for signs of heat exhaustion or heat stroke. Infants and young children, of course, need much more frequent attention.
Never Leave Children, Disabled Adults or Pets in Parked Vehicles
Each year, children and pets left in parked vehicles lose their lives from hyperthermia. Hyperthermia is an acute condition that occurs when the body absorbs more heat than it can handle. Hyperthermia can occur even on a mild day. Studies have shown that the temperature inside a parked vehicle can rapidly rise to a dangerous level for children, pets and even adults. Leaving the windows slightly open does not significantly decrease the heating rate. The effects can be more severe on children because their bodies warm at a faster rate than adults.
Flooding and Notifications
Floods are among the most frequent and costly natural disasters. Conditions that cause floods include heavy or steady rain for several hours or days that saturates the ground. Flash floods occur suddenly due to rapidly rising water along a stream or low-lying area. Know the difference between the different types of flood-related weather notifications.
Flood or Flash Flood Watch indicates flooding or flash flooding is possible in your area.
Flood or Flash Flood Warning indicates flooding or flash flooding is already occurring or will occur soon in your area.
If you live in a high risk flooding area, consider the following before a flood occurs:
- Elevating appliances such as furnaces, hot water heaters, and electric panel in your home
- Installing "check valves" to prevent flood water from backing up into the drains of your home
- Constructing barriers to stop floodwater from entering the building
- Sealing basement walls with waterproofing compounds
- Purchasing flood insurance
Driving Safety
- Six inches of water will reach the bottom of most passenger cars causing loss of control and possible stalling
- A foot of water will float many vehicles
- Two feet of rushing water can carry away most vehicles including sport utility vehicles (SUV's) and pickups
- If you are not able to see the depth of the flood waters, turn around. More than half of all flood-related drownings occur when a vehicle is driven into hazardous flood water.
- Do not drive around road barricades as the road could be washed out
What to do in a Flash Flood
- Be prepared to evacuate to higher ground
- Do not attempt to cross a flowing stream on foot. Six inches of fast moving water can knock you off your feet
- If the vehicle stalls, abandon it immediately and seek higher ground. Rapidly rising water may engulf the vehicle and its occupants
- Be especially cautious at night when it is harder to recognize flood dangers
Severe Weather
Thunderstorms affect relatively small areas, compared with most other storms. The typical thunderstorm is 15 miles in diameter and lasts for 30 minutes — but whatever their size, all thunderstorms are dangerous.
Severe Thunderstorms produce large hail or winds of at least 58 mph. Some wind gusts can exceed 100 mph and produce tornado-like damage. That’s why many communities will sound their outdoor sirens for damaging straight-line winds. When threat of a severe thunderstorm exists, stay inside a strong structure. Mobile home occupants should go to a more permanent structure.
Thunderstorm Winds may occur during thunderstorms; thunderstorms can produce straight-line winds that exceed 100 miles per hour. For this reason you should treat severe thunderstorms just as you would tornadoes. Move to an appropriate shelter if you are in the path of the storm.
Hail is a form of precipitation consisting of solid ice. Hail during storms causes nearly $1 billion in damage every year. Most hail is about pea-sized. Some hail is the size of baseballs, at times it may reach grapefruit-size. Large hail stones fall faster than 100 mph and have been known to cause severe injury and even death.
Lightning Safety Tips
- NO PLACE outside is safe when thunderstorms are in the area
- If you hear thunder, lightning is close enough to strike you
- When you hear thunder, immediately move to safe shelter: a substantial building with electricity or plumbing or an enclosed, metal-topped vehicle with windows up
- Stay in safe shelter at least 30 minutes after you hear the last sound of thunder
Indoor Lightning Safety
- Stay off corded phones, computers and other electrical equipment that put you in direct contact with electricity
- Avoid plumbing, including sinks, baths and faucets
- Stay away from windows and doors, and stay off porches
- Do not lie on concrete floors, and do not lean against concrete walls
If you are caught outside with no safe shelter anywhere nearby the following actions may reduce your risk:
- Immediately get off elevated areas such as hills, mountain ridges or peaks
- Never lie flat on the ground
- Never shelter under an isolated tree
- Never use a cliff or rocky overhang for shelter
- Immediately get out and away from ponds, lakes and other bodies of water
- Stay away from objects that conduct electricity (barbed wire fences, power lines, windmills, etc.)
Myths and Facts About Lightning
Tornadoes
In a House With a Basement
Avoid windows. Get in the basement and under some kind of sturdy protection (heavy table or work bench), or cover yourself with a mattress or sleeping bag. Know where very heavy objects rest on the floor above (pianos, refrigerators, waterbeds, etc.) and do not go under them. They may fall down through a weakened floor and crush you.
In a House With No Basement
Avoid windows. Go to the lowest floor, small center room (like a bathroom or closet), under a stairwell, or in an interior hallway with no windows. Crouch as low as possible to the floor, facing down; and cover your head with your hands. A bath tub may offer a shell of partial protection. Even in an interior room, you should cover yourself with some sort of thick padding (mattress, blankets, etc.), to protect against falling debris in case the roof and ceiling fail.
In an Apartment, Dorm or Condominium
If you live in an apartment that is on an upper floor, get to the lowest level of the building that you can immediately. This could be an underground parking garage or a neighbor’s first floor apartment. Then move to the most interior area possible, away from windows. If you live in a high-rise apartment building, you may not have enough time to get to a lower level, so picking a place in the hallway in the center of your building is the best idea such as a stairwell. If that is not available then a closet, bathroom or interior hall without windows is the safest spot in your apartment during a tornado. Power loss during a tornado storm is common, so avoid elevators and keep a flashlight handy.
In an Office Building, Hospital or Store
Follow instructions from facility managers. Go directly to an enclosed, windowless area in the center of the building -- away from glass and on the lowest floor possible. Then, crouch down and cover your head. Interior stairwells are usually good places to take shelter, and if not crowded, allow you to get to a lower level quickly. Stay off the elevators; you could be trapped in them if the power is lost.
In a Mobile Home
Seek safe shelter. Even if your home is tied down, you are probably safer outside, even if the only alternative is to seek shelter out in the open. Most tornadoes can destroy even tied-down mobile homes; and it is best not to play the low odds that yours will make it. If your community has a tornado shelter, seek shelter immediately. If there is a sturdy permanent building within reasonable distance seek shelter there. Otherwise, lie flat on low ground away from your home, protecting your head. If possible, use open ground away from trees and cars, which can be blown onto you.
At a School
Follow the drill. Go to the interior hall or room in an orderly way as you are told. Crouch low, head down, and protect the back of your head with your arms. Stay away from windows and large open rooms like gyms and auditoriums.
In a Vehicle
Vehicles can be extremely dangerous in a tornado. If the tornado is visible, far away, and the traffic is light, you may be able to drive away from its path by moving at right angles to the tornado. Otherwise, park the car as quickly and safely as possible -- out of the traffic lanes. Get out and seek shelter in a sturdy building. If in the open country, run to low ground away from any cars (which may roll over on you). Lie flat and face-down, protecting the back of your head with your arms. Avoid seeking shelter under bridges, which can accelerate the wind while offering little protection against flying debris.
In The Open Outdoors
If possible, seek shelter in a sturdy building. If not, lie flat and face-down on low ground, protecting the back of your head with your arms. Get as far away from trees and cars as you can; they may be blown onto you in a tornado.
In a Shopping Mall, Large Store or Stadium
Listen for instructions from building security. Watch for others. Move as quickly as possible to an interior bathroom, storage room or other small enclosed area, away from windows. Move away from any glass.
In a Church or Theater
If possible, move quickly but orderly to an interior bathroom or hallway, away from windows. Crouch face-down and protect your head with your arms. If there is no time to do that, get under the seats or pews, protecting your head with your arms or hands.
Tornado Safety Fact Sheet
Severe Winter Weather
- Monitor National Weather Service forecasts, statements, watches, and warnings for the latest information on a developing winter storm. National Weather Service websites and NOAA Weather Radio All Hazards provide a direct link to this information
- Winterize your vehicle. Keep antifreeze fresh. Assure you have a strong car battery. Use snow tires
- Keep a winter survival kit in your car
- Winterize your home by installing storm windows, adequate insulation and caulking, and weather-stripping doors and windows
- Stock extra batteries for radios and flashlights
- Consider a safe alternate heat source, and keep a ready supply of fuel
- Listen to NOAA Weather Radio All Hazards, local radio, or television, or monitor National Weather Service websites for the latest weather reports and emergency information
- If you plan to be outside, dress in layered clothing and avoid over-exertion
- Wear a hat; most body heat is lost through the top of the head
- If your vehicle becomes stranded, stay with it until help arrives. Do not try to walk for help during a winter storm, as conditions may suddenly worsen with little advance warning