As the walking part of any tour up to the glacier takes a long time, and ends at the first icefall (a frozen waterfall, draping a natural step in the land underneath), many tourists book helicopter tours from one of the several local airlines, which usually drop their guests between the first and second icefalls, for a guided 1–2 hour walk through the broken ground atop the glacier. Although the glacial landscape changes almost daily, given the glacier's unusually fast flow, and some walks including passages through ice tunnels, they are still considered quite safe and only somewhat strenuous. In June 2010, an Australian tourist died of a heart attack during a guided hike of the glacier.