Dress warmly while reporting on a polar vortex. Stay dry. Hydrate often.

Your mother told you these things. But we forget, especially while spending our days going from one warm building to another.

During the most recent polar vortex, I saw a young photojournalist running cool water over his hands. They were red, and stinging. Not good. He had worn gloves on the assignment, but they weren’t heavy enough, and he had pulled them off to answer his cell phone.

I figured he wasn’t the only journalist struggling with signs of frostbite. So, I asked around and came up with this tip sheet to help you prepare for next time the temperature outside makes your kitchen freezer feel like a warm summer breeze.

Technology tip: Take a spare sock

The oldest advice: Take a pencil. Lead doesn’t freeze; the ink in your pen will.

It’s not as easy to keep batteries charged in a smart phone or camera. Most of our gadgets aren’t really designed to operate below zero. My iPhone with its lithium ion battery went from 28 percent charged to dead in about 10 minutes the other day.

There are scientific reasons for this sudden drainage. Or you can just trust me. Meanwhile, here are preventative measures:

• Put your phone in an inside pocket. Yes, it’s more awkward to answer. But the phone will be warmer when it’s closer to your body.
• Got a sock that lost its twin? Give your phone its own little sleeping bag. There are classier and more costly insulated phone cases, too. Got a second sock? Stuff your extra batteries there.
• Pack an external charger. Or two.
• Tell your editor to keep the conversation short, then stow that phone right away.

Hands, feet and head

Your feet are easier to protect. Get a good pair of socks, preferably not cotton, which can make things worse when they’re wet. For the same reason, buy waterproof boots or add waterproofing to the boots you have.

And pack a spare set of socks, just in case.

Hands are harder, because you need them to be quite nimble at times.

• Several possibilities:
  • Wool fingerless mittens. You can flip the mitten part open to get to your fingers.
  • Gloves with those magic fingers that allow cell phone use.
  • Brown jersey gloves. I know; I just said cotton is a problem. But I use them as a backup and as a second (or third) glove layer when it’s really cold. They usually cost a buck, so I don’t panic if they get lost. Throw a pair or two in your car as backup.
  • Hand warmers. You can slip them in gloves or in a pocket.

Your mom may have told you that most body heat goes out from your head. Not really. If you left your leg uncovered, more heat would leave there than from your head because there’s more surface area exposed.

Few people go out in a polar vortex wearing shorts. So the only exposed skin is your head. In that way, mom was right.

Wear a hat. And not just a ball cap. Yeah, it might mess up your hair. No one will complain. I also use my jacket hood as a double cover when I’m bicycling into work.

Protect the base

Finally, the base. One editor recommended flannel pajamas underneath jeans. A cheap solution if you’re wear PJs. Otherwise, lots of high-tech solutions have trademark symbols attached to indicate the products breathe well and dry fast.

I actually prefer outer layers. My rain pants do wonders in the cold, and I can easily remove them when I get back to the newsroom.

And that’s my last advice: Get inside. The story will still be there after you’ve warmed up a bit.