What is a heat wave? What defines one, and how does it form?

NEW YORK (WABC) -- A summer heat wave is once gain upon us, with temperatures soaring into the 90s and real-feels in the triple digits.

But what is a heat wave? What defines one, and how does it form?

Heat waves can form when a high-pressure system moves into a region and stalls.

The system can force warm air downward, acting like a cap that keeps the cool air near the surface from rising.

What qualifies as a heat wave can vary greatly from region to region, but in the northeast or Great Lakes region, a heat wave is generally considered to include three straight days of temperatures in the 90s or higher.

RELATED | NYC heat wave: Tips, resources for coping with extreme heat
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It's hotter than normal, and it has been like this for several days. What you're experiencing is a heat wave. How did it form?


Should you find yourself in a heat wave, try to limit your time outside to the mornings and the evenings, when the air will be coolest.

You'll also want to drink plenty of water throughout the day.

ADDITIONAL HEALTH AND SAFETY TIPS FOR PROTECTION AGAINST THE HEAT

- Go to an air-conditioned location, even if for a few hours.
- Stay out of the sun and avoid extreme temperature changes.
- Avoid strenuous activity, especially during the sun's peak hours: 11 a.m. to 4 p.m. If you must do strenuous activity, do it during the coolest part of the day, which is usually in the morning between 4 a.m. and 7 a.m.
- Remember: drink water, rest, and locate shade if you are working outdoors or if your work is strenuous. Drink water every 15 minutes even if you are not thirsty, rest in the shade, and watch out for others on your team. Your employer is required to provide water, rest, and shade when work is being done during extreme heat.
- Wear lightweight, light-colored clothing when inside without air conditioning or outside.
- Drink fluids, particularly water, even if you do not feel thirsty. Your body needs water to keep cool. Those on fluid-restricted diets or taking diuretics should first speak with their doctor, pharmacist, or other health care provider. Avoid beverages containing alcohol or caffeine.
- Eat small, frequent meals.
- Cool down with a cool bath or shower.
- Participate in activities that will keep you cool, such as going to the movies, walking in an air-conditioned mall, or swimming at a pool or beach.
- Make sure doors and windows have tight-fitting screens and, in apartments where children live, and window guards. Air conditioners in buildings more than six stories must be installed with brackets so they are secured and do not fall on someone below. Window guards can prevent children from falling out of a window and suffering serious injuries or even death. Screens keep mosquitoes that can spread West Nile Virus out of your home and keep cats from falling out of windows.
-Never leave your children or pets in the vehicle, even for a few minutes.

KNOW THE WARNING SIGNS OF HEAT ILLNESS

Call 911 immediately if you or someone you know has:
- Hot dry skin.
- Trouble breathing.
- Rapid heartbeat.
- Confusion, disorientation, or dizziness.
- Nausea and vomiting.

If you or someone you know feels weak or faint, go to a cool place and drink water. If there is no improvement, call a doctor or 911.

KEEPING YOUR PETS SAFE

- Avoid dehydration: Pets can dehydrate quickly, so give them plenty of fresh, clean water.
- Walk your dog in the morning and evening: When the temperature is very high, do not let your dog linger on hot asphalt. Your pet's body can heat up quickly, and sensitive paw pads can burn.
- Know when your pet is in danger: Symptoms of overheating in pets include excessive panting or difficulty breathing, increased heart and respiratory rate, drooling, mild weakness, unresponsiveness, or even collapse.

IMPROPER FIRE HYDRANT USE

The improper opening of fire hydrants wastes 1,000 gallons of water per minute, causes flooding on city streets, and lowers water pressure to dangerous levels, which hamper the ability of the Fire Department to fight fire safely and quickly.

Use "spray caps" to reduce hydrant output to a safe 25 gallons per minute while still providing relief from the heat. To obtain a spray cap, an adult 18 years or older with proper identification can go to his or her local firehouse and request one.

ENERGY-SAVING TIPS

During periods of intense electrical usage, such as on hot, humid days, it is important to conserve energy as much as possible to avoid brownouts and other electrical disruptions.

While diminishing your power usage may seem inconvenient, your cooperation will help to ensure that utility providers are able to provide uninterrupted electrical service to you and your neighbors, particularly those who use electric powered medical equipment or are at risk of heat-related illness and death:

- Set your air conditioner to 78F or "low."
- Run appliances such as ovens, washing machines, dryers and dishwashers in the early morning or late at night when it is cooler outside to reduce heat and moisture in your home.
- Close doors to keep cool air in and hot air out when the air conditioner is running.
- Keep shades, blinds, and curtains closed. About 40 percent of unwanted heat comes through windows.
- Turn off air conditioners, lights, and other appliances when not at home, and use a timer or smart technology to turn on your air conditioner about a half-hour before arriving home. Keep air conditioner filters clean.
- If you run a business, keep your door closed while the air conditioner is running.
- Tell your utility provider if you or someone you know depend on medical equipment that requires electricity.

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Watch Jeff Smith's video for an in-depth look at how the system works and what Con Edison has to do to keep the juice flowing, and what you can do to keep your bills down.   

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