I'm stealing this directly from MMBTS:

Moose Mtn – Opening Weekend – TRAILS ARE SNOW COVERED!
May 15th, 2009
It’s been 166 days since the Moose Mtn road closed for winter, taking away access to our beloved singletrack. We’ve endured a long winter, and we’re all excited that May 15th is finally upon us. That’s right – the date that the road opens every spring for vehicle traffic. This spring, Mother Nature hasn’t been as kind as in recent years, and parts of the winter snowpack still remain in areas that don’t get a lot of direct sunlight. Add to that, the fact that Kananaskis has received snow this past Tuesday, Thursday, and as recently as this morning, and what we have is a mess! That’s right, Bragg Creek residents had to brush the snow off their shuttle trucks this morning in order to get out of the driveway for the long weekend.

As you’re making your long weekend riding plans, please remember that while Calgary may finally be warm and dry, Moose Mountain is not!! A lot of manhours were put into the trail network there last summer, not to mention the work of over 80 volunteers(a new record) who came out to the inaugural 2009 trail day last Saturday. The trails are very wet and snowy right now, and the ground is soft from the recent thaw. These are the sort of conditions where riding the trails leads to damage and erosion that will take all summer to repair. Please be respectful of the work that the trailbuilders and wicked awesome volunteers have done, and stay off the trails until they’ve had a chance to dry out a little. If you’re absolutely dying to do something bike-related, grab your shovel and go do a little buffing on your favorite trail – that’s something we can all benefit from! A little patience will go a long ways for our trails!

I'm going out tonight to mark a line for a future trail day, but I'll grab some pics and post up my impressions of conditions.  Based on MMBTS' description, stay off the trails unless they're dry.  Fish Creek is calling...