Question
If grass is damaged by walking on it when frozen what is the long term result. Is there any damage next spring? We are in a northern climate where winter lasts at least 4 months

Answer
I wish I could be optimistic about your concerns.  Unfortunately, the fact is, the damage caused by walking on frozen Grass can be bad enough to kill it.

The problem is the frozen leaf tissue in the fragile Grass blade.  When the Grass is not frozen, it yields to pressure.  But because it is brittle when frozen, it breaks under pressure, all the way down to Soil level.

Our Oregon State Extension Service addressed this very question:

extension.oregonstate.edu/news/story.php?S_No=1009&storyType=garden

Turfgrass specialist Tom Cook warned Oregon gardeners, 'If turf receives concentrated foot traffic while it is frozen, individual Grass plants may be killed, leaving you with dead spots come Springtime.'  The Lawn Institute also cautions homeowners, 'Stay Off a Frosty Lawn':

www.thelawninstitute.org/education/?c=185223

Despite the high Sugar content that works as a natural antifreeze, Grass blades still contain a lot of Water.  That's what makes them brittle.  Foot traffic ruptures individual cells and shatters individual leaf crowns, and THOSE are needed for regeneration.

Any kind of damage caused by walking -- or sledding, or snowball fighting, or even snow angel-making, can be difficult or even impossible to repair.  Points out Lawn Institute, 'Why the injury is caused is debated, some claim the cells of the plant are damaged because the Water in the leaf tissue is frozen and the tissue is brittle.  Others believe that the crystallized Water punctures the Grass blades in thousands of places causing wounds that cannot heal.  Whatever the cause, the damage cannot be refuted.  Injury to frost covered Grass will not be seen right away but will be noticeable 12 to 48 hours after the damage is done.  Often the injured grass will get a purple or black hue.  The Grass will then turn brown as it dies.  Dead Grass will leave areas for Weeds to germinate.  Damaged Grass that does not die will be more susceptible to disease.'

Canadian Winters are long and chilly.  It's hard to imagine completely avoiding all that fun, all those months, for the sake of a perfect Lawn in Spring.

If you have Harpin Protein available up there, keep it in stock, ready to use next Spring.  This would be SPRAYED on damaged Lawn areas, with very little watered into the ground; that's the most efficient, most effective way to repair those sections of the Lawn.  Grass not damaged during Winter will also grow better through Spring if treated with this stuff.  Down here, it is packaged in small envelopes and sold as 'Messenger' in certain garden centers.

Wish I could tell you not to worry.  Be vigilant, and in Spring, take action to treat any damage quickly.

THE LONG ISLAND GARDENER