1. Melting Ice and Boiling Water in the Mountains: A History and Physics Essay 
Harvey V. Lankford, MD, Leslie R. Fox, PhD 
Wilderness & Environmental Medicine 
Volume 28, Issue 4, Pages (December 2017)
DOI: /j.wem
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2. Figure 1
Bar graph shows the net energy in kJ/kg needed for stages of heating snow or ice into 0°C water at rising altitude. The black bar shows the net energy needed to raise snow or ice from low temperatures to the melting point (WARM). This is a small amount, but it increases with altitude. The white bar shows the net energy needed for phase change to convert 0°C ice to 0°C liquid water at the same temperature (MELT). This is a very large but constant amount. The sum of WARM + MELT is shown on Figure 2.
Wilderness & Environmental Medicine  , DOI: ( /j.wem )
Copyright © 2017 Wilderness Medical Society Terms and Conditions

3. Figure 2
Line chart shows the net energy in kJ/kg needed for stages of heating snow or ice into boiling water at rising altitude. The upper solid line is the sum WARM + MELT, the increasing net energy needed to raise snow or ice from low temperatures to the melting point (WARM) and then convert it with phase change from frozen ice to liquid water at the same temperature (MELT). The lower dashed line is BOIL, the decreasing net energy needed to bring resultant liquid water to incipient boiling at increasingly higher altitudes and lower pressure at which the boiling point temperature falls. The divergence of the 2 lines confirms the Shipton rule that at higher altitudes WARM + MELT is greater than BOIL.
Wilderness & Environmental Medicine  , DOI: ( /j.wem )
Copyright © 2017 Wilderness Medical Society Terms and Conditions