Heat pump coils covered in ice, including a couple of inches into the fan blades...?

The fan sounded like it was still running this morning but wasn't because the blades are "iced into" the ice on the inside of the coils. I turned to emergency heat and coils are still ice covered tonight. It's below freezing right now so not too excited about hosing down the coils. Will it harm the unit to run while fan blades are frozen solid? What options do I have here? The heat/ac people have been here several times over the last 7 years while I've been learning the issues with a heat pump, never any major problems but I don't seem to ever hear the hissing of it defrosting...... Thanks for any help!