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Monday, July 17, 2017

Melt Out at Paradise on Mount Rainier

Yesterday, July 16th was melt-out day at the official snow measuring site at Mount Rainier.


Located at roughly 5500 ft, this melt-out day is about 1 week later than typical for the past 100 years (information from Mark Albright, UW Research Scientist).  Here is an interesting table showing the mean melt-out dates by decade at Paradise Mt Rainier:

Decade     Date     No. of Years
----------------------
1910s       16 July     2*
1920s       10 July      9**
1930s        3 July       10
1940s        1 July       10
1950s        17 July       9**
1960s        5 July        10
1970s         21 July      10
1980s        10 July       10
1990s        15 July       10
2000s        10 July        10
2010s         1​6 July      8***

* 1917 and 1918, ** 1925 missing, 1950 missing, *** 2010-2017

As you can see, there is no real trend towards earlier melt-out, which would be a sign of global warming.  That will come, but later in the century.

What about a much lower site?  Such as Stevens Pass (about 4000 ft above sea level)

The snowpack melted out this year on 7 June 2017 at the Stevens Pass SNOTEL site, with the melt-out this year tied for ​11th ​latest out of the past 37 years (the length of record there).

Mean melt-out dates by decade showing a trend towards later melt-out of the snowpack in recent years:

1980s: 30 May
1990s: 1 June
2000s: 2 June
2010s: ​4 June (thru 2017)

Similar to Paradise, the snowpack is holding on later into the warm season.  

 The maintenance of our snowpack into the summer helps maintain our streamflow into the summer, which is good for fish and water resources.   By the middle of the century we expect the situation to change as warming causes more of our precipitation to fall as rain in the mountains.


from Cliff Mass Weather and Climate Blog http://ift.tt/2u1eILI

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