Melting Season Begins

February 14, traditionally celebrated as Valentine’s Day, could also be considered the beginning of our melting season. What is so special about February 14 that would help usher in the spring melt?  The latitude of North Dakota ranges from near 46° N to 49° N.  Interstate 94 runs roughly along the 47° N latitudinal line and using that as a reference, on February 14 the angle of the sun at solar noon will be 30° above the horizon.  Once the Sun reaches that height above the horizon, melting usually occurs, especially on black topped roads and other darker surfaces nearly every sunny day, even with temperatures near 0° in the afternoon.

On the winter solstice just before Christmas, the Sun angle at solar noon is just 19.5° off the horizon on the 47° N latitudinal line.  The recovering in the past 6 weeks of 10 + degrees makes a significant difference in the amount of radiation (energy) this area receives.  Granted, chemicals on the road also assist in melting, but even untreated roads on a sunny day from this point forward will record some melting.  Generally unnoticed, melting will also be occurring on the snow pack as well.  Plus, any bare soil exposed on agricultural land will also quickly warm the soil and melt the snow pack in those areas.

Because most of the region has recorded limited snowfall this year and in turn little if any snow cover, it is that additional warming created by more absorption of solar radiation by the bare soils that will aid in additional warmth not usually experienced this time of year which could hasten an early spring, if the big snows stay away.

Spring frequently does not arrive in North Dakota and northern Minnesota until April, yet, the beginning of that process starts this time of year.   Happy Melting Season.

Daryl Ritchison