This time of the year (December) seems like a good time to talk about snow loads. I am not talking about the questionable stories told around campfires although there are usually plenty of that! Snow loads you need to be concerned about would be the weight of snow on the roof of your RV, on your tent, (if you go winter camping or store your RV outside) or on a storage area for your RV or camping equipment. Of course, if you live or winter in the sunbelt, you don't have to worry about snow or snow loads. Snow loads on residential buildings are usually taken into consideration in the design and construction but if you get an unusually large amount of snow for your area they may be of some concern.
Water weights about 8 lbs per gallon and there is about 7.5 gallons of water in a cubic foot, making water around 62 lbs per cubic foot. Snow is frozen water. The weight of snow varies a lot, depending on whether it is light and fluffy, wet, or packed. Light, fluffy snow may be around 7 lbs per cubic foot. More average snow is around 15 lbs per cubic foot but drifted and compacted snow can easily hit 20 lbs. That means a foot of light fluffy snow on the roof of your RV will weigh about 7 lbs on each square foot of roof. Wet or packed snow could weight 20 lbs per foot. What does that mean? Assume you have modest, 25' RV. With a width of about 8', that's 200 square feet. Just fluffy snow a foot deep over the whole area would weigh 1400 pounds!! Drifted and compacted snow could put 2 tons (4000 lbs) of weight on your roof! Not only might that begin to stress the structural integrity of the roof itself, it could put pressure on other components from load bearing walls to suspension and tires. Imagine driving with 2 tons of extra weight up that high! That would significantly raise the center of gravity, screw up handling, and increase the risk of roll over. I estimated the weight of snow on the roof of my 11 1/2' slide-in camper at more than 1200# resulting in some saved in roof panels before I could shovel it off. I've heard of snow build up in mountain areas sufficient to pop the tires on travel trailers left out in the winter weather.
If your RV is stored in a shed, carport, or garage, the RV should be safe but the snow load on the structure may be of some concern. If the weight exceeds the roof capacity, the whole thing could come crashing down on your RV. So even if your RV is normally protected against the elements, you will want to monitor the accumulation of snow on the roof of your storage facility and may need to take steps to remove the snow periodically. Steep roofs, like those on alpine structures, allow snow to slip off, but lesser slopes, quite common on garages, barns, sheds and carports, can allow significant snow accumulation and you may have to manually remove it to prevent damage. Walmart ran into some problems when they built stores in the snow belt along the East Coast based on the same flat roof design they used in Arizona and California where they didn't have to worry about snow.
Clearing snow from your RV roof can be kind of tricky. The best way to do it is from a sturdy ladder alongside your RV. Climbing up on the roof subjects you to many hazards. The obstacles (vents, lights, antennas, racks, etc.) may be hidden in the snow. You may damage them inadvertently trying to shovel or sweep the snow off the roof. Or you might trip over them and fall. That snowy RV roof is also very slippery. It is a long way to the ground and even if you land in soft snow, its going to hurt! For added stability, have someone steady the ladder. If you don't have someone to steady the ladder, never put an A-frame ladder so the steps are perpendicular to the side of your RV. Your efforts to push the snow off the roof may push the ladder over. Place it so the steps are parallel to the side of the unit or lean it against the RV for maximum stability. You still need to exercise caution because you could push yourself off the ladder, but at least the ladder will be less likely to tip and dump you on the ground. Another tip: don't wait for the snow to get too deep before clearing it off. You can sweep 3-4" of snow off the roof with a broom unless it is excessively wet or has partially melted and frozen to the surface. Deeper amounts become harder to remove, requiring more effort and increasing the risk of a nasty fall or damaging components buried in the snow. Removing it quickly also reduces the chances of it freezing to the roof surface. Clear snow after each storm. Letting it sit will give a chance to get solid and to stick to the roof. Plus, the accumulation from the next storm will add a lot of weight. Even it it doesn't do any major structural damage, it may begin to cave in the roof between the rafters and loosen seams. If you live where you get 1 foot or more of snow at at time and your RV is left outside, consider laying plywood or OSB panels on the roof. It will more evenly distribute the load and give you something to scrape the snow off of instead of running the risk of damaging your roof itself. Rubber and fiberglass roofs may crack when you walk on them it it gets cold enough. Metal roofs won't crack but you may loosen the seams. Try not to walk on the unsupported spaces between the seams of a metal roof. Doing so can cave in the roof and separate the seams.
Snow can sometimes get deep enough on other vehicle roofs to cave them in. The smaller area, somewhat curved shape, and closely spaced supports beneath the roof of most cars and trucks makes them less susceptible than RV roofs, but it can still happen. And, of course, if you don't clear the snow you have to contend with the added weight and shift of center of gravity, neither of which improve handling on slick roads. For example, a foot of snow on a 4'x4' pickup roof could weigh from 100 to 300 pounds. Besides that, deep accumulations on the roof can dislodge and impair visibility while driving, so brush the snow off your vehicle roof before hitting the road. Snow blowing off your vehicle could be considered an unsafe load and you could be held liable for damages if it causes an accident.
Snow can accumulate on tents when you're winter camping, quickly exceeding the load rating of the poles and the fabric. Once again, your best bet is to remove the snow as quickly as possible to avoid damage. It would definitely not be nice to have your tent collapse on you and bury you in a foot or more of snow! In addition to the threat of being crushed or at least bruised by the collapsing snow load, damaged tent poles could become spears that inflict serious injury. Sometimes you can simply slap the tent from the inside from time to time to knock the snow off before it gets too thick. If you allow a couple of inches of snow to accumulate, there is a strong possibility that warmth from inside the tent will melt the snow next to the fabric and then cold outside temperatures and dropping temperatures inside will cause it to freeze, binding the snow tightly to your tent and making it very difficult to remove. Brush off as much snow as you can with a brush, broom, or pine bough, then bang the inside of the tent to loosen any ice. It may be very difficult to monitor snow accumulation at night, especially if you're lucky enough to be able to sleep during the storm. Any shelter you can make use of to reduce the snow accumulation will help. Be very cautious about setting up your tent under trees. Snow will accumulate in the branches and may be dislodged and fall on your tent -- or you! -- with disastrous results. Snow may be knocked loose by wind, by its own weight, or loosened by heat rising from a stove or campfire, or maybe even from your own body heat escaping from your tent. Double wall tents will generally fare better in snowy conditions but you'll still need to keep the rain fly cleared of snow. Using a tarp over any tent and then frequently shaking the snow off of it is a fairly easy way to avoid snow accumulation.
Boats stored outside are also subject to snow loading. You will want to monitor snow build up on your boat or boat cover and clear it off before it causes any damage.
Snow drifts are created by the wind shifting snow around. Snow is picked up by strong winds and deposited wherever there is a windbreak that slows the wind. Drifted snow can be very beautiful, almost like it had been sculpted by an artist, but drifts can also present significant vehicle hazards. I've seen 4WD vehicles stuck in the snow because it was deep enough that the vehicle undercarriage "floated" on the snow and couldn't get any traction. Hitting a deep drift at any significant speed can be about like running into a brick wall. Snow drifts do have one good quality: they make a good source for cutting snow blocks to build an igloo or a good place to dig a snow cave or snow trench for shelter in a survival situation.
If you're going to be staying in the snow for more than a day or so, without heat, it might be better to build an igloo than to stay in your tent. A foot of snow provides as much insulation against the outside temperatures as the R-13 fiberglass insulation in the walls of your home. Building an igloo is not easy and it may take several tries before you can get the right shaped dome to be self sustaining. Even Les Stroud (Survivorman) had trouble. You need pretty well packed snow for your building blocks. If the snow is loose or not deep enough to cut building blocks, you may be able to build an igloo by rolling basket-ball sized snow balls and stacking them in the shape of a dome. Pack snow between the balls to create a solid dome large enough for you and your companions. Then cut some sticks about 2' long and push them into the dome all over about 8-12" apart. Then dig into the dome and hollow it out until you reach the ends of the sticks. Make your opening on the downwind side of your igloo. Hang a heavy blanket over the "door" or roll a snowball big enough to close it off. You will want to leave some ventilation so you don't suffocate but you don't want any strong breezes getting in. If you use any kind of combustion inside for heat or light you should make a small opening toward the top of the dome to allow smoke and fumes to escape. The opening should be a little on the downwind side of the roof so wind doesn't drive snow and cold air into it and the wind passing over it will help draw bad air out. You'll also need at least one low vent (usually the entrance) to allow fresh air to enter.
Like most situations in life, surviving a snow storm can be done -- if you are properly prepared and take appropriate measures to protect yourself and your family and equipment.
Let it snow!
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