A satellite image from early Wednesday shows massive Hurricane Ian approaching the coast of Florida.

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CNN  — 

Deadly Hurricane Ian – downgraded Thursday to a tropical storm as it crawls across Florida – smashed into the state’s southwestern coast on Wednesday, destroying homes and cutting power to millions.

As emergency crews scramble to aid those still trapped in their homes, more than 2.5 million residences and businesses were without power early Thursday. Ian is expected to bring strong winds and heavy rains to parts of Florida, Georgia and the Carolinas over the next few days, the National Hurricane Center said.

“Ian is going to be a life-changing event. This is a very powerful, catastrophic storm that is going to do significant damage,” said Eric Silagy, CEO of Florida Power & Light.

If you’re without power during the hurricane, here’s what you can do to stay safe.

The basics

It’s crucial to ensure electric appliances are disconnected to avoid any harm or damage from power surges, according to the Federal Emergency Management Agency.

FEMA also recommends keeping freezers and refrigerators closed to help maintain cooler temperatures for food preservation.

For good measure, turn off the main power breaker in your house and do not use any devices that are wet.

Watch out for carbon monoxide

Generators should only be used outdoors and placed more than 20 feet away from doors and windows, even if they are closed.

The devices emit carbon monoxide, which is a poisonous gas that can be lethal.

“(Carbon monoxide) is an odorless, colorless gas that kills without warning. It claims the lives of hundreds of people every year and makes thousands more ill,” the US Centers for Disease Control and Prevention says.

The CDC also recommends ensuring battery-operated carbon monoxide detectors are placed near sleeping areas.

Discard flooded and too-warm food

Food that has been comprised by floodwater should not be consumed and should be thrown away, officials advise.

Refrigerated food that reaches at least 40 degrees Fahrenheit should be discarded, FEMA says

If you have medications that require refrigeration, find out how long they can be without it before their safety expires.

Use flashlights instead of candles

Avoid using candles during a blackout if possible. If you must use them, keep them away from anything that could catch fire and do not leave them unattended, the CDC says. Ensure a fire extinguisher is available and those around you know how to use it.

Avoid floodwaters as much as possible

Although it can be unavoidable when dangerous flooding is happening, stay out of floodwaters as much as possible.

Floodwaters can lead to the risk of drowning or being washed away from the intensity of flow and winds. They can hide dangerous downed power lines and can also be chemically harmful because they contain germs, dangerous substances, human and livestock waste, the CDC says.

Check on your neighbors and loved ones

When it’s safe, reach out to people around you to make sure they are doing well.

Those who have medical equipment that require power, like respirators, should be taken to locations with generators or a friend’s or neighbor’s home that hasn’t been impacted.

And remember: The elderly and young children are especially vulnerable to extreme weather.

Protect your pets

Do not leave your pets behind if you evacuate during a power outage and never tie them outdoors during extreme weather events. “If you leave your pets behind, they may be lost, injured – or worse,” the CDC says.

Take the proactive step to contact your local emergency management office to learn about whether they have opened shelters to accommodate pets. To find a shelter near you, check out the Humane Society website. Be mindful that diseases can spread among pets and humans during extreme weather events.

Conserve power when possible

Power can be rationed by turning off and unplugging nonessential lights and appliances. Don’t use large appliances like ovens or washing machines if you can avoid it.

Thermostats should be set to 68 degrees because heightened demand could trigger more blackouts – or extend them.