Can we get scab infection with snow?

The really unusual weather we've had so far this spring, and a forecast for who knows what the next two days or so, brings up the old question about whether it is possible to have an apple scab infection period with wetting by melting snow. The answer, of course is, yes it is. If there is enough wetting to initiate ascospore discharge and deposition on susceptible tissue in the tree, then prolonged wetting from melting snow (48 hr at near freezing temperatures) can result in infection. We saw it happen in 1990- a year that gave us three snows and 13 nights below freezing after green tip - and we still ended up with decent apple and peach crops.  Logic says that if the snow blankets frozen ground before ascospore discharge, it would prevent discharge into the air, negating impaction of the ascospores in the tree and therefore would not result in infection.

Speaking of the wild weather this spring, without looking back, I don't recall a year when we had this much prolonged cold after green tip. So far, at the AREC, we see only a little damage of king bloom that was showing some color (a little bit beyond tight cluster) Sunday morning when the temperature dipped to 26. The coldest time seemed to come with the snow and there was probably air movement that brought cold to higher elevations in the orchard blocks that were more advanced than lower areas (a freeze rather than a frost). Once we get through this, hopefully the week or more of colder weather will be recognized as having been beneficial because it delayed bud and reduced susceptibility to later frosts.