With lightning, tornadoes, and hail storms, summer is the most likely time that most people will experience a substantial power outage. With summer power failure a lot of threats, from food safety to heat stroke, become apparent. Read the helpful information below to see how you can best prepare for these threats.

Even if you aren’t convinced that hardcore preparedness is for you, it would still be difficult to argue against the possibility of a disaster that takes out the power for a couple of weeks. Basic emergency preparedness is important for everyone, not just us “crazy preppers.”
Beware of dehydration and heat-related illnesses
One of the most serious concerns that sets apart a summer power outage from that of other times of the year is the heat. When you don’t have so much as a fan to move the air around, heat-related illnesses and dehydration are strong possibilities.
Dehydration is the state that occurs when you use or lose more fluid than you take in, and your body doesn’t have enough water and other fluids to carry out its normal functions. Your electrolytes are out of balance., which can lead to increasingly serious problems.
Symptoms of electrolyte imbalances include dizziness, fatigue, nausea (with or without vomiting), constipation, dry mouth, dry skin, muscle weakness, stiff or aching joints, confusion, delirium, rapid heart rate, twitching, blood pressure changes, seizures, and convulsions.
Dehydration can lead to very serious side effects, including death.
Following are the most common dehydration-related ailments.
Heat cramps: Heat cramps are painful, brief muscle cramps. Muscles may spasm or jerk involuntarily. Heat cramps can occur during exercise or work in a hot environment or begin a few hours following such activities.
Heat exhaustion: Often accompanied by dehydration, heat exhaustion is a heat-related illness that can occur after you’ve been exposed to high temperatures.
There are two types of heat exhaustion:
Water depletion. Signs include excessive thirst, weakness, headache, and loss of consciousness.
Salt depletion. Signs include nausea and vomiting, muscle cramps, and dizziness.
Heat stroke: Heat stroke is the most serious form of heat injury and is considered a medical emergency. Heat stroke results from prolonged exposure to high temperatures—usually in combination with dehydration—which leads to failure of the body’s temperature control system. The medical definition of heat stroke is a core body temperature greater than 105°F, with complications involving the central nervous system that occur after exposure to high temperatures. Other common symptoms include nausea, seizures, confusion, disorientation, and, sometimes, loss of consciousness or coma.
How to Treat Dehydration
People who are suffering from dehydration must replace fluids and electrolytes. The most common way to do this is through oral rehydration therapy (ORT). In extreme cases, fluids must be given intravenously. In a disaster situation, hospitals may not be readily available, so every effort should be made to prevent the situation from reaching that level of severity.
Humans cannot survive without electrolytes, which are minerals in your blood and other bodily fluids that carry an electric charge. They are important because they are what your cells (especially those in your nerves, heart, and muscles) use to maintain voltages across cell membranes and to carry electrical impulses (nerve impulses and muscle contractions) across themselves and to other cells. Electrolytes, especially sodium, also help your body maintain its water balance.
Water itself does not contain electrolytes, but dehydration can cause serious electrolyte imbalances.
In most situations, avoid giving the dehydrated person salt tablets. Fresh, cool water is the best cure. In extreme temperatures or after very strenuous activities, electrolyte replacement drinks can be given. Sports drinks such as Gatorade can help replenish lost electrolytes. For children, rehydration beverages like Pedialyte can be helpful. (Source)
Store lots of water
One of the best ways to avoid the heat-related problems above is to store lots of water.
Each family should store a two week supply of water. The rule of thumb for drinking water is 1 gallon per day, per person. Don’t forget to stock water for your pets, also.
Try to keep cool during the blackout
This is easier said than done when it’s 105 and you can’t even run a fan.
Keep hydrated. Your body needs the extra water to help produce sweat, which cools you off.
Change your schedule. There’s a reason that people who live near the equator close down their businesses and enjoy a midday siesta. Take a tepid shower and then, without drying off, lay down and try to take a nap. At the very least, do a quiet activity.
Play in the water. Either place a kiddie pool in a shaded part of the yard or use the bathtub indoors. Find a nearby creek or pond for wading or swimming.
Soak your feet. A foot bath full of tepid water can help cool you down.
Avoid heavy meals. Your body has to work hard to digest heavy, rich meals, and this raises your temperature. Be gentle on your system with light, cool meals like salads, cold soups, and fruit.
Be very conscious of food safety
According to the Red Cross, if your freezer is half-filled and is not opened the entire time that the power is out, the food in it will remain sufficiently frozen for up to 24 hours. If it is completely filled, your food should remain safe for up to 48 hours. If the worst happens and your freezer full of meat does spoil, keep in mind that most homeowner’s and renter’s insurance policies will pay for their replacement, but unless you’ve lost a whole lot or your deductible is very small, it may not be worth making a claim.
Another way to combat the potential losses of a long-term summer power outage is to use other methods for preserving your feed. Canning and dehydration are not grid-dependent and can save you a whole lot of money and prevent a mess of rotting meat in your freezer.
Food and a way to prepare it
There are two schools of thought regarding food during a power outage. One: you need a cooking method that does not require the grid to be functioning. Two: you can store food that doesn’t require cooking.
Sanitation needs
A common cause of illness, and even death, during a down-grid situation is lack of sanitation.
For cleaning, reduce your need to wash things. Stock up on paper plates, paper towels, and disposable cups and flatware. Keep some disinfecting cleaning wipes and sprays (I don’t recommend using antibacterial products on a regular basis, however in the event of an emergency they can help to keep you healthy.) Use hand sanitizer after using the bathroom and before handling food or beverages – there may be a lot more germs afoot in a disaster.
If you are on a septic system, with no risk of the toilet backing up into the house, simply store some water for flushing in the bathroom. (At the first sign of a storm, we always fill the bathtub for this purpose.) Add the water to the tank so that you can flush.
Light
Lighting is absolutely vital, especially if there are children in the house. Nothing is more frightening than being completely in the dark during a stressful situation. Fortunately, it’s one of the easiest things to plan for, as well as one of the least expensive.
Some lighting solutions are:
Garden stake solar lights
Flashlights (don’t forget batteries)
Hand crank/solar lantern
Other options are long-burning candles or kerosene lamps, but during a summer outage they would be less desirable, since they add heat to an already overly warm situation.
Entertainment
Nothing grates on a parent’s nerves more than a refrain of, “I’m boooooredddd.” Many kids are accustomed to almost-constant electronic entertainment, so the loss of that can be quite stressful.
Keep a box of off-grid entertainment supplies in an easy-to-access place. Make one up for the different members of the family and make these items things that the kids are not allowed to play with at any other time so that they are novel and interesting when the time comes to use them. Include things like stationary supplies, notebooks, pens and pencils, sharpeners, colors or coloring pencils, markers, glue sticks, glitter, puzzles, activity books, games, stickers…make it a treasure trove! Be sure you include all of the supplies needed for each activity because it’s hard to find things when your home is only lit by candlelight.

The biggest dangers you are likely to face in a summer power failure are the spoiling of frozen and refrigerated foods and being unable to obtain water. This is why it's important to have ample water stored and to have plenty of emergency food sources that don't require refrigeration or cooking.

Perhaps one of the best pieces of advice from these tips is the trick of filling the bathtub at the onset of every storm, for refilling the toilet so that you can keep flushing if you lose power.

This is an excellent article with a lot of really useful tips. For even more advice, head over to Ready Nutrition.