The 60-meter (yard) high wall of ice holding back a portion of Lake Argentina breaks apart spectacularly in cycles of one year to several years, but always in summer, and is one of Patagonia's top tourist attractions.

"This is the first time the glacier breaks up in winter. It could be related to global warming as rising temperatures affects ice friction," said Los Glaciares National Park director Carlos Corvalan.

The Perito Moreno glacier, one of the world's largest, measuring 275 square kilometers (106 square miles) and five kilometers (three miles) wide at its mouth, is located 2,800 kilometers (1,740 miles) southeast of Buenos Aires.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.