Question: In which year did this American pioneering mountaineer and writer, after whom this scattering of glaciers and snowfields located on the southern flank of Mount Rainier in Washington was named, climb Mount Rainier?
{'answer': '1870', 'supporting_facts': [['Van Trump Glacier', 0], ['Van Trump Glacier', 1], ['P. B. Van Trump', 0], ['P. B. Van Trump', 1]]}