Is it permissible to perform ablution with snow, and is it permissible to perform tayammum with it?

Wetness is not sufficient for ablution; rather, water must flow over the limb. If snow melts and flows over the limb when wiped, then ablution performed with it is valid. However, tayammum (dry ablution) is not valid with snow because it is not sa'id. Sa'id refers to the surface of the earth, including dust, sand, and stone. If one finds snow but no means to melt it, and fears the prayer time will expire, he should pray with tayammum and then repeat the prayer.