I am considering using the 18′ yurt in an application in Alaska (summer and winter). The yurt would be put up to temporarily to cover an access hatch to an equipment room which is under ground, while the hatch is open. It would protect the equipment in the equipment room protected from blowing dust, rain, snow while the hatch is open. The yurt would only need to be in place for a few days at a time. In the winter the temperature can get as cold as -40F. Would the poles still maintain the flexibility and strength at that temperature.

Once up they should be fine. Warm poles in a sleeping bag that has bottles of hot water if you are putting the dome up when it is very cold. Remove poles one at at time.

Same question about the fabric.

Not effected by cold.

I’ve read other questions about snow accumulations and believe that would not be a problem.

Be sure to read the wind warnings also.

Do the sides of the yurt go all the way to the ground with some extra length to prevent water from coming underneath?

Yes, but you will still need a site that drains water away. You could also single a strip of material under the skirt to extend it.

If there is extra length (like a skirt) I would probably put sand bags on top of the skirt to give added from rain water coming underneath.

There is a skirt but if you use sand bags also tie them to the clip cords on the dome.

Also, in this application I would need to build up the yurt next to the access hole and then lift it up and over some guard railings that go around the opening. How do you think the yurt would perform under these circumstances?

It is freestanding and light to pick up and move.