This Spring Happening will vary greatly from place to place. It will depend on wind, air temperatures, cloud cover, and kind of water body. What will be ice free first? Rivers, lakes, or ponds?
What to look for:

Pick a local lake or pond to watch.
As the days get warmer, keep your eyes open! The ice on lakes usually turns a gray color shortly before it melts. It often melt all in one day!

Watch in your neighborhood and around school. If you think you are the first person to see this event, ask your teacher to submit your name to the Wolf Ridge website (see table below.)

Ice seems to take forever to melt -- why?

It takes a LOT of heat from the sun to melt the ice that's covering Minnesota's lake and streams.

It might take days, or even weeks of warm weather to melt it all. How fast the ice melts depends on . . .

  • how thick is the ice to begin with?
  • how cold that ice is to start with (30 degrees is much warmer ice than ice that is - 10 degrees?)
  • is the sun shining down through clear skies or through clouds?
  • is water moving over the ice (wind on the lake or water flowing in a river?)
  • is the lake or river deep or shallow?

Once the ice leaves the lake or river, all the animals who have been trapped under all winter start to come out. You can expect to see turtles, frogs, toads, insects, and even mammals like the beaver come out to enjoy the warm air of spring.
Why care about ice out dates?

Ice-out dates will be very different from year to year, but overall trends in when the ice melts in lakes and rivers can help us measure global warming. This is because water warms up and cools off very slowly compared to the earth's air and ground. If lakes and rivers are staying icy longer each year, we have evidence that the climate is cooling off. If the ice covers lakes and rivers for less and less time over many years, we might be experiencing a warming trend.

Wolf Lake Ice Out Dates
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
 2005
5-2
5-4
4-30
5-7
5-13
5-2
4-19
4-25
4-4
5-2
4-30
5-2
4-26
 4-18
Cool Facts
Heat of Fusion

It takes the same amount of heat to raise the temperature of a bucket of liquid water 80 degrees Celsius as it does to change the same bucketful of ice into liquid water. This "heat of fusion" is what makes ice work great to keep pop cold in your cooler on a hot summer day.
Turn, Turn, Turn

As ice melts, the cold water that forms sinks to the bottom of the lake. This forces water that has been on the bottom to come to the surface. The result is a mixing effect called "spring turnover." Spring turnover is very important because the mixing water brings oxygen and nutrients to all parts of the lake.

No Place like Earth!

Earth is the only place we know of in the whole universe where temperatures are just right so that water can be a mixture of solid (ice), liquid (lakes, rivers, ground water . . .), and gas (clouds, humid air . . .)
A solid that doesn't sink!

When most substances freeze, they take up less space (less volume.) This means most solids are heavier than their liquid form, and sink. Not so with water! Water actually EXPANDS when it freezes. Since frozen (solid) water is lighter than the same amount of liquid water, ice floats. This means fish, turtles, frogs, insects, and other critters can all survive the winter UNDER the ice in the warmer water below. If ice didn't float, lakes would freeze from the bottom up, exposing whatever lived in it to those -20 nights (way too cold!)

Think About It!

  1. How would life on earth have to be different if ice were to sink instead of float?
  2. How would things be different for people if it only took a little bit of energy to melt ice?
Explore the Web
When will the ice go out? Check to see if you lake or river, or one nearby, has been followed before.
The whys and hows of watching for ice out.
What makes water so special? Read this, then take the quiz!
Follow the water cycle and more.
Find the watershed for your local river, lake, or stream.
15 things you and your class can do to make a difference in your watershed.
All of these sites have more technical information that may be of interest to older students.
Learn more about ice and lakes in these Wolf Ridge classes:
In the Frozen Lake Study aquatic ecology class, students will examine the ecosystem of Wolf Lake under the ice. Working in groups, they will explore the lake through holes drilled in the ice, from inside ice houses, and by sampling the ice itself. Studies will include ice depth and structure, lake bottom structure, plankton sampling, and possible catch and release ice fishing opportunities.
Lake and Stream Study are aquatic ecology classes. Students will examine the physical, chemical and biological properties of Wolf Lake or Sawmill Creek. Wearing boots which are provided, and working in small groups, the students will test temperature, pH and dissolved oxygen, and, in the stream, velocity. They will use nets to collect and examine aquatic animal life, and will evaluate the health of the lake/stream based on their findings.
Date School Town Observer Comments