It doesn't exactly resist melting per say. The two snowpacks are very different in structure.
Coastal snowpack falls usually very dense and when it melts the snow under the surface layers is already water saturated basically. In Colorado/continental snowpacks, despite the many skiers compacting things, is much drier and looser snow that is easily undermined by the snowmelt happening on the surface and trickling through. It creates big undermined areas and will even wash away the bottom part of the snowpack in areas leading to sudden, very unpredictable slides. The already wet snowpack on the bottom of the costal snowpack doesn't wash away like that and stays stuck to the ground which is much more stable.
ABasin actually installs a couple of sensors on steep slopes to detect running water under the steepest runs. When they detect running water the steeps are done for the year so the undermined snowpack doesn't slide on guests (about 20 years ago they had an inbounds wet avalanche that killed one person in spring).