Southern Arizona law enforcement officials say the desert's cold nighttime temperatures can be just as dangerous as scorching summer days for illegal immigrants.
U.S. Border Patrol agents say a group of 27 men, women and children was found last month in the mountains south of Sierra Vista.
They say about half of the group was taken to a hospital for treatment of possible exposure.
Border agents say dehydration is a leading cause of distressed people and deaths due to excess layers of clothing, rugged terrain and the false assumption that less water is needed during cold weather.
The Arizona Daily Star says many immigrants try to cross the desert during the winter holidays because they believe there's going to be reduced immigration enforcement.
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