Second largest glacier in Switzerland; a clean valley glacier with many tributary glaciers.

 

Data collected:  118 length measurements have been recorded during the past 133 years since 1882. 

 

Studies:  glacial history has been reconstructed using radiocarbon dating of fossil wood, tree ring analysis, archeological studies, historical photographs, and written records for the past 450 years. 

 

Dated 8 advance and retreat cycles for the past 9,500 years.  Of these, 7 occurred during the past 3,300 years or so.  The last advance began around 1800 and ended in 1859--the end of the Little Ice Age.  Its rate of advance averaged 30 feet/year.  This last advance and retreat cycle has occurred over 200 years with the glacier advancing about 2,000 feet and retreating over 10,000 feet.

 

Lost almost 2 miles in length since 1859.

 

Retreat rates have accelerated from 20 feet/year during 1882-1985 to 92 feet/year during 1985-2015--over 4 times faster.  The rate over the past 15 years was 135 feet/year.

 

Since 1882, 117 out of 118 measurements were retreats.

 

As of 2018, five tributary glaciers that were all connected in 1990 to the main valley glacier have retreated and disconnected from it.  As a result, they no longer give a supply of higher elevation ice to the valley glacier below.  The last one was connected in 2015 and disconnected in 2018.