We’re slowly creeping toward the heart of winter in the United States and bouts of snow and ice are already sweeping across the country. We have plenty of ways to keep up with the forecasts as winter sets in. Whether you’re looking at an app on your phone or scrolling through social media, it can be tough to know who or what to trust when you’re searching for information about an upcoming winter storm.

Here are some rules about winter storm forecasts to keep in mind as the threat of snow and ice grows in the coming weeks.

1. It’s hard to predict snowstorms more than a few days out

The seven-day forecast your favorite meteorologist shares on the nightly news is rooted in sound science. Predictions are pretty reliable up to about a week in advance, with confidence wavering a bit when active weather is in the mix. But even with all the improvements over the years, winter storms are still a tough nut to crack.

The difference between snow, ice and rain is determined by a tiny bit of warm air above the surface, and that’s hard to forecast more than a few days ahead of time.

Pay attention to the possibility for snow or ice about five days in advance. That’s when you can start to tell the general track a storm may take.

You’ll want to pay attention to the possibility for snow or ice about five days in advance. Five days is around the point when you can start to tell the general track a storm may take. A storm’s track is extremely important when it comes to determining who sees the different types of winter weather.

Forecasters are usually confident enough to predict snowfall totals about three days in advance. These totals can change as meteorologists receive up-to-date data from weather models and observations around the approaching storm. It’s frustrating to have to watch and wait to change your plans, but forecasts are accurate enough to have at least a day or two of warning before the snow begins. 

2. Don’t listen to Facebook. Really.

Diet tips and medical advice aren’t the only topics to avoid on Facebook. It’s common to see predictions of huge blizzards or devastating ice storms while you scroll through your feed. Anyone can create a Facebook page and sound authoritative as they pump out nonsense to the masses. This is a huge problem when it comes to fake or misleading weather information.

If you see a post that calls for tons of snow and ice, take it with a grain of salt and resist the temptation to share it with your friends and family. Seek out posts from the National Weather Service or a trusty broadcast meteorologist from a local television station. Some of those local weathercasters are guilty of peddling hype on social media, too, but most of them know the importance of accurate forecasts and won’t steer you wrong. 

3. Blockbuster snowstorms are rare

There’s a reason not to trust those posts exclaiming that the next storm of the century is right around the corner. It’s really hard to get a big snowfall. All the historic storms that people reminisce about every year are memorable for a reason.

What constitutes a big storm differs from place to place. An inch of snow could shut down New Orleans, but the same dusting can go virtually unnoticed in Boston or Minneapolis. On average, a city will see a big, memorable snowfall every decade or two.

Just like a huge tornado or a scale-topping hurricane, everything has to come together just right to create a mammoth snowstorm that people talk about for generations. It just doesn’t happen that often. When you see someone talking about feet of snow that could shut everything down for days on end, it warrants a bit of caution until trustworthy sources are ringing the alarm.

4. Snow is manageable. Ice isn’t.

Winter storms aren’t all about snow. Snow is manageable to a certain extent if you have the right vehicle and crews are able to keep the roads clear. Ice is an entirely different headache.

The difference between fluffy snow and a thick crust of ice is often just a couple of degrees of warmth a few thousand feet above our heads. A tiny layer of air that’s just above freezing can turn a potential snowstorm into a significant ice storm. Big cities like Washington, D.C., and New York often find themselves right on that fine line between snow and slop.

Pay close attention to forecasts when meteorologists call for ice or they’re uncertain about what kind of precipitation you’ll see during a storm. We can deal with snow, but ice is something even the most winter-hardened folks can’t handle. 

5. Prepare for power outages instead of getting stuck inside

The first things to go in the grocery store when the forecast calls for snow are bread, milk and eggs. Those won’t help you much when the power goes out. We’ve conditioned ourselves to prepare to stay inside for an extended period of time after a winter storm, but preparing for power outages is more important than worrying about what you’ll eat if you’re cooped up for a few days.

If the forecast only calls for a couple inches of snow, it’s probably not necessary to raid the grocery store and stock up like a squirrel. However, if meteorologists predict freezing rain or a heavy, wet snow, stocking up on non-perishable and easy-to-eat foods is a wise choice. 

It’s more common to endure a power outage during a winter storm than it is to get stuck inside for days at a time. Trees and power lines struggle under the immense weight of snow and ice. Cars can slide into power poles. The strain of too many homes running their lights and furnaces can cause blackouts. If that happens, milk and eggs won’t do you much good. 

In addition to bread, keep some ready-to-eat canned foods on hand — something like ravioli, PB&J, and fruit cocktails — so you’re not scrambling to find something you don’t have to heat up.

Bottles of water for drinking and jugs of water for toilets and hygiene are good to have if a water main bursts and you lose service.

And, of course, it’s good to have batteries and flashlights on hand. It’s convenient to use your cell phone light in a pinch, but that won’t cut it when the lights are out all night.

Dennis Mersereau writes about the weather. His work has appeared in Forbes, Washington Post and Mental Floss, among others. He previously ran The Vane, a popular weather blog, and is the author of The Extreme Weather Survival Guide.