|Alf's High Rustler, 16 March 2014|
For a (nearly) north facing aspect like upper High Rustler, with a pitch to the cat track of about 35 degrees, the first day of potential sun is about Feb 11th, and that's only at solar noon. Note that right at the top it is close to 45 degrees, so the first sun there is even later (note how it is in the shade in the photo above, which was taken about 90 minutes prior to solar noon).
Today, March 16th, a north facing aspect needs to have a pitch of about 47 degrees to totally avoid the sun (there are some exceptions, such as when there is even steeper terrain adjacent and to the south). A run like High Rustler gets sun for a few hours, enabling for some nice light for turns and shadow skiing (for those who enjoy an ego stroke). Of course, the sun is more indirect than on other aspects, so the snow still keeps longer on these aspects than on others.