CANAZEI, Italy (AP) — Rescuers using drones are resuming the search for an estimated 13 people unaccounted-for following an avalanche in northern Italy that killed at least seven people and is being blamed in large part on rising temperatures that are melting glaciers. After rain hampered the search Monday, sunny weather on Tuesday allowed helicopters to bring more rescue teams up to the avalanche site on the Marmolada glacier, east of Bolzano in the Italian Alps. A huge chunk of the glacier cleaved off Sunday, sending torrents of ice, rock and debris down the mountainside onto unsuspecting hikers below. At least seven people were killed, and a further 13 remain unaccounted-for, officials said.