You might try this info i received last month from the Canyonlands Park Ranger...
''Hi again, Matt.
All of our backcountry sites are available year-round, but they are
sometimes inaccessible in the winter months due to ice, snow, or rockfalls.
We don't close the sites, but Nature often makes a trip ill-advised.
Backcountry visitation is very low here from late November through
February, mainly because of the shorter daylight hours and night-time
temperatures that are often well below freezing. The average lows are in
the low 20s to the low 30s, but we often have lows in the single digits in
December and January.
Probably the biggest hazard in the winter is icy conditions hidden by a
layer of fresh snow. It can be a beautiful time to be here, but also a very
dangerous time for backcountry travel. You don't really need a reservation
in the Winter, but it is a good idea to call ahead and check on conditions
before you arrive.
Thanks, and I hope you have an excellent Thanksgiving weekend.
Bruce
Canyonlands National Park Reservation Office
435-259-4351 M-F 8am-12:30pm MST
(fax) 435-259-4285
canyres@nps.gov''