What to do in Cold Weather

Cold Weather: People

Winter in Minnesota provides the opportunity to get breathtaking footage but it’s important to protect ourselves, and help protect each other from its hazards. The U.S. motion picture industry’s “Guidelines for Working in Extreme Cold Temperature Conditions” explains risk factors, symptoms, and prevention of the two most common hazards when working in the cold: hypothermia and frostbite, along with what to do if someone is showing signs of either.

If you’re considering gathering footage outdoors in winter, it’s important to weigh carefully these guidelines and whether you can plan and execute a shoot that takes them into account. Questions include:

• Is severe weather on the way?
• Does everyone have adequate clothing?
• Are you all watching each other for symptoms?
• Who’s keeping track of how long you’ve been out in the cold?
• Can anyone on your shoot get indoors quickly whenever they need to warm up?

Understanding Wind Chill

Wind chill expresses the additional cooling effect of wind in cold weather. The National Weather Service’s publication Wind Chill Temperature Index includes precautions, as well as a chart of temperatures crossed with wind speeds that allows you to estimate wind chill.

Windchill temperatures are associated with what are called frostbite times: the time it takes for frostbite to develop in exposed skin. Given an ambient temperature of zero degrees Fahrenheit (-18 Celsius) in fifteen-mile-per-hour winds, it only takes half an hour for frostbite to develop in skin directly exposed to these conditions–fairly common in Minnesota winters.

Wind in cold weather not only puts people at risk of frostbite in exposed skin. As we know from a short walk across campus on a blustery day, wind drives cold air through and/or past layers of clothing. This is an additional consideration for risk of hypothermia.

Frostbite can develop in any part of the body that gets cold enough, exposed to the air or not. Fingers and toes are of frequent concern. Extra socks can compress the foot and decrease circulation, thus shortening the time before toes get dangerously cold. One longtime outdoorsperson advises students he leads on winter nature walks to bring a piece of styrofoam to stand on, in addition to wearing cold weather boots that fit properly.

It’s easy enough to get from the National Weather Service the current ambient temperature and estimated wind speed as measured at the nearest weather station (for Northfield, that’s at Stanton Airfield, about seven miles east of campus). Smartphone apps such as weather.com can be helpful as well. Temperature at the weather station might not be much different from where you are (low-lying areas can be quite cold), but wind speed can vary tremendously over short timespans and depending on precise location. A handheld thermometer/anemometer with built-in windchill calculator is available for checkout from the Production Office.

Cold Weather: Equipment

The CAMS production students at the heart of Carleton’s production community depend on having access to gear that works properly. It’s important to know the risks to our equipment from shooting in cold weather. If you damage something you’re still responsible for its repair or replacement, even if you’ve taken precautions described here.

None of our cameras are rated by their manufacturers for operation below freezing. Chuck Westfall of Canon discusses why in an article on ProPhotoHome.com.

National Geographic photographers Sisse Brimberg and Cotton Coulson also offer tips for cold weather shooting.

People sometimes think of keeping a camera warm inside winter clothing, but there are several problems. It doesn’t take many times of unzipping vital layers to get cold–dangerously so, in extreme conditions–and nothing is worth that. But the insidious factor for equipment is condensation. We know water damages electronics, so of course, we want to keep precipitation (including snow) off of equipment, but condensation is a bit trickier.

Condensation happens when a cold thing encounters warm air. Any humidity in the warm air will deposit on the cold thing as condensation. This includes putting cold gear inside a warm coat, as well as bringing gear indoors on a cold day. Surprisingly, it’s easy to risk equipment damage at the very moment we might think we’re bringing it out of harm’s way. Here’s how it works.

A camera body or a microphone lets in air and its humidity quite easily. When condensation forms, it coats every electronic component inside, potentially turning it into an expensive paperweight.

Here’s a very important preventative measure to take: While you’re still outdoors, seal the equipment in an airtight container, such as large Ziploc bag or, in a pinch, plastic tub. (If you’re returning gear to the Production Office and you don’t have such a thing, please do call extension 5434 and ask whoever answers to meet you at the door with one.) This way, when you bring it indoors, condensation forms on the outside of the container while the gear inside very slowly comes up to room temperature–overnight is a good rule of thumb.

If you have reason to think there’s any moisture at all in a piece of electronics, don’t power it on. Remove any battery, open any door or cover, and turn a fan on it–overnight is again a good rule of thumb.

These are important techniques to have in your kit. However, there’s no guarantee some last little bit of condensation hasn’t formed somewhere deep inside a piece of equipment. If damage results, you are responsible for repair or replacement.

Camera covers for Sony NX5Us and dSLRs are available for checkout from the Production Office. It’s possible to tape a chemically-activated handwarmer packet to the inside of a camera cover, although there are several important precautions. Chemically-activated handwarmer packets can reach 165 degrees Fahrenheit, hot enough to burn you and far hotter than any camera’s range of operating temperatures. Clearly, the heat could damage components. Additionally, as air warms near a handwarmer, condensation can form, either as liquid or frost, from any humidity present. This is an immediate cue to shut down the equipment and dry it as described above.

Batteries are best stored cool and used warm. Shooting with a battery that’s physically cold is chemically inefficient and will give startlingly short battery life. A battery that’s cold enough will read as dead on the camera’s battery meter, even though there is a charge stored in it. The best use for a handwarmer packet is in an external pocket where you can put your hands when you don’t need them and also keep several batteries warm, then rotate batteries in and out of the camera (checking closely for moisture). Unheated exterior coat pockets are usually about as cold as it is outside.

Canon calls the 60D “water and dust resistant.” Clearly this is not intended to be “waterproof.” Sony makes no claims about the NX5U as in any way resistant to water or dust.

It’s worth considering getting at least some shots on your list from indoors. With luck, the entryway of a building on or near location is just warm enough to help people and gear stay warm, and just dry enough condensation doesn’t form. Often foyers are difficult to work with, either for being overheated or surprisingly humid.

With planning, the desired angle is sometimes possible from a window or doorway. Here’s a technique for keeping reflections out of your shot when shooting through glass. The key is recognizing where the reflections are coming from—almost always from inside the room you’re in—and blocking them from the camera’s view. Sometimes you can simply position your body between the camera and the light. Other times, someone can hold up a coat behind both you and the camera. It’s also possible to build a little hood of Cinefoil or other black wrap — available in the Production Office — to put between lens and window.