Art Wolk, two-time Grand Sweepstakes bulb forcing champion at the Philadelphia Flower Show and author of "Garden Lunacy," says, "First, there's a lot of antifreeze in these plants, so... they can survive just fine with their leaves above ground over winter.  And, more importantly, flower stem development occurs independently of the leaves....  So tell everyone who has greenery up already not to worry, and not to do anything to try and "help" the bulbs.  They may bloom a month earlier than usual or they may bloom pretty much on schedule if it takes the soil an especially long time to warm up in the spring, but they should bloom just fine.  The leaves are tough and the flowers are still safe inside the bulb...  Just warn people especially not to cover them with a lot of any kind of mulch to try and protect them.  They don't need any help, and I've seen frozen mulch do a lot more damage to emerging flowers than weird weather ever could."