Lake Michigan Coastal Dunes
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Lake Michigan Coastal Dune Home
Introduction to Lake Michigan Coastal Dunes
Features and Types of Dunes
Wind, Sand and Coastal Dunes
Climate, Dune, Lake and Seasonal Factors
Methods, Results and Research Students
References and Links to More Information


 

Environment - Wind

Lake Michigan coastal dunes are subject to winds that vary seasonally in strength and direction.

Overall (Annual) Wind Patterns
Mean monthly wind speeds recorded at Muskegon, MI, are between 4 and 6 m/s (9-12 mph). Peak gusts greater than 22 m/s (50 mph) have been recorded in every month of the year. The winds are more frequently from the west than the east throughout the year.

To read the windrose (right), look for the percentage of time (indicated by dashed circles) that winds come from a specific direction (such as west). Colors indicate the speeds of the winds from the indicated directions (see color key).

The windrose is based on thirty years (1961-1990) of wind data collected in Muskegon by the National Weather Service.

Muskegon wind rose: annual

Wind speed is a defining variable for coastal dunes. For sand to move, wind speeds must exceed a threshold level related to sand grain size. This threshold level is roughly 5-6 m/s for Lake Michigan dune sands. The amount of sand movement is also related to wind speed: the volume of sand transported by wind increases exponentially with increases in wind speed. More sand will move in a single storm with high winds than will move with months of wind speeds just above the threshold.

Strong winds do not automatically produce sand movement. If surface sand grains are affected by surface moisture, snow, ice, ground freezing, vegetation or other complicating variables, sand movement will be greatly reduced or halted completely.

Winter winds moving sand and snow in Hoffmaster State Park.
Winter winds move sand and snow along beach (from south to north) in Hoffmaster State Park (January 2005).

The wind direction determines the direction of sand movement. The direction of the strongest winds is more important than the average wind direction or even the direction of the most frequent winds. Wind direction is always reported as the direction the wind is coming from.

Seasonal Wind Patterns
Consider the seasonal pattern of winds as measured at Muskegon, MI. Keep in mind that the strongest winds can move the most sand, and the sand will move according to the direction of the strongest winds.   

Summer winds are weaker than winds during the rest of the year. The strongest summer winds are from the south and southwest. Muskegon wind rose: summer
Autumn winds are strong and show a lot of variability. Easterly winds are not as strong as westerly winds. Strong winds from the south and north will move sand past the dunes along the beach. Muskegon wind rose: autumn
Winter winds are also strong. The strongest winds are from the west and northwest. There is still potential for transport along the beach during strong north and south winds. Some strong east winds could move sand towards the lake where it is deposited on the coastal ice. Muskegon wind rose: winter
Spring winds are not as strong as autumn and winter winds. There is considerable variability in the direction of the strongest winds. Muskegon wind rose: spring
Wind roses are generated from Muskegon wind data (1961-1990) using WRPLOT View software from Lakes Environmental available at www.lakes-environmental.com.

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Last updated 03/23/10.