A teachable moment, for some of course - we've found that asking volunteers to estimate their mobility immediately after a bad weather event (snow) gives everyone a more reliable sense of availability for the next event. All the volunteers in the world are worthless if they can't get to your shelter to work. You can also make plans to move necessary people around - 4x4 pickups along snow routes for example. The same folks responding as little as a month later tend to overestimate their ability to respond in a similar event.

If your friends aren't receptive to personal preparedness and responsibility for the next snowpocalypse (snow chains, a car kit and a full gas tank to creep down the snowy road), this might get them thinking about a more communal approach for the next one (like proactively taking a work from home day the day before snow, or better plans for sheltering in place, and keeping folks off the roads during the snow event).

Stay warm!