Weather Wednesday: When the Great Lakes Freeze

Satellite image of Great Lakes February 2015. NOAA.


As of February 25, 2015, the Great Lakes are over 85% ice covered and the coverage is growing weekly.  glsea_curOther than the obvious impact to shipping, what does this really mean?

When the Great Lakes experience heavy ice cover as they have in the winters of 2014 and 2015 there are a multitude of impacts.  Some are beneficial and some are problematic and some are both.

For example, evaporation takes place over open water even in the winter time.  At least partially because evaporation was inhibited in the winter of 2014-15, Lake Michigan water levels last summer increased dramatically over the summer of 2013.  Some of the impacts included reduced usable recreational beach areas. On the positive side, the higher water levels mitigated some of the need to dredge channels and harbor entrances especially along the eastern shore of the lake.  As of February 25, the water level on Lake Michigan was a whopping 21-inches higher than a year earlier and was 8 inches higher than the long term average.  Snow melt and rainfall also are a factor, but the reduced evaporation plays a role. lighthouse

Snowfall amounts are also affected when the lakes freeze.  Lake Effect Snow basically shuts down once the lakes freeze over, a welcomed break for motorists in the Great Lakes snow belt areas.

Heavy ice cover also tends to influence spring and even summer weather in areas close to the lakes.  The temperatures in communities near Lake Michigan were noticeably cooler than inland communities in the spring and summer of 2014, far cooler than the usually welcomed moderating effect of the lake.  One benefit of the late spring is to fruit growers.  The cooler weather delays the blossoming of fruit trees to the extent that the threat of frost damage from isolated cold snaps is mitigated.  And the normal micro-climate of shoreline communities is more pronounced in years when the lakes are ice-covered.

Arcadia, MI. Cool summer of 2014. Author.

Long lasting ice cover also affects the water temperature of the Great Lakes.   Even the normally more moderate lakes remained quite cool for swimming and other warm weather recreation in the summer of 2014.  It is worth noting that there was still visible ice on Lake Superior into June of 2014 and some water temperatures in Lake Michigan were still in the upper-30 degree range on Memorial Day weekend!!  The reduced water temperatures impact how anglers approach their prey.  And the development of algae can also be affected.

It is likely that the ice cover of the lakes will continue to expand for at least a few more weeks this year.

Extension Disaster Education Network: By Land and By Sea

Most EDEN delegates are familiar with Land Grant colleges (program instituted in 1862), but not everyone may be familiar with Sea Grant colleges. The Sea Grant program was instituted in 1966 when Congress passed the National Sea Grant College Program Act. The program is administered by the National Oceanic and Atmospheric Administration (NOAA) and is based in Silver Spring, Maryland. The nation-wide network is composed of 32 university-based programs that work with coastal communities.Sea Grant extension is represented in every coastal and Great Lakes state and in America Samoa and Puerto Rico.  Sea Grant Extension operates in much the same way as does Cooperative Extension–by taking the knowledge to the communities.

Although not every Sea Grant college is represented in EDEN, we do have Sea Grant member institutions and delegates. Among those delegates are Bob Bacon (South Carolina Sea Grant Consortium and formerly served on the EDEN Executive Committee ) and Jack Thigpen (North Carolina Sea Grant). Jack currently represents Sea Grant on the Executive Committee.

Michael Liffmann, Sea Grant Program Director for Extension and EDEN delegate, hosted several of us last week in Silver Spring. During our two-day meeting, we agreed that disaster-resilient communities is one theme common to both Cooperative Extension and Sea Grant Extension, and to focus on implementing a project developed by Mississippi-Alabama Sea Grant Consortium. The Coastal Resilience Index: A Community Self-Assessment was recently released and the first facilitator traning will take place February 22-23, 2011 in Biloxi, MS. The training is available to Sea Grant agents and Extension agents. More information about the Silver Spring meeting and outcomes will follow.

Attending the meeting: (back row, left to right) Mike Liffmann, David Bryant, Abby Lillpop, Rick Atterberry, Jack Thigpen. (front row, left to right) Virginia Morgan, Jody Thompson, Pat Skinner, Deborah Tootle, Bill Hoffman.

Regards, Virginia Morgan, EDEN Chair