Frost & Hoarfrost

Just before this latest cold snap that has produced some nice window frost designs we had a day of freezing fog. This fog created hoarfrost on some of the willow bushes that were still sticking out of the deep drifts around the house.
The main difference between the two is window frost forms on a pane of glass when exposed to below freezing temperatures on the outside and moist air on the inside room. Water vapor from the air condenses as frost on the inside surface of the window pane. Crystal growth is strongly influenced by scratches or other film on the window and can grow into elaborate patterns. (photo 1)

Hoarfrost develops when water vapor condenses directly into ice on out side objects such as twigs or grass stems. When the frost forms minute ice crystals covering the ground it is just called frost. But if the frost grains grow larger they are called hoarfrost crystals. (photo2)

We are back to cold weather after a long spell of wind and snow. Today the low was -43F and forecasted to stay cold for a while.

Still only ravens around and while there has been a lot of bird migration movement in some of the lower 48 states it will be some time before we see much movement this far north. See the post at
http://minnesotabirdnerd.blogspot.com/2009/03/big-move-tonight.html for moreinformation on radar tracking bird movements at night.

Restless Ravens

Spring is slowly making its way north and the ravens are starting to feel the effect of the longer days. After seeing only two ravens during the dark days of deep winter, we see them almost every day. Sometimes just a lone bird, but more often a pair and they have started their spring courting displays.

Today we had 5 ravens around the house looking for scrapes of fish left in the yard by Toby are Chesie. With the wind back around 30 mph they love to work the wind currents around the house and at times seem to float in mid air.

Next month will see the return of our snow buntings the real harbinger of spring. It always such a loving sound to step out and hear their song drifting across the yard.

Roaring March

Catch up notes March 1-5
March came in with a bang, high winds, fresh snow, and blowing snow that created blizzard conditions that at times had the visibility down to less than 150'. With all the fresh snow and winds that peaked out at 62 mph more snow was added to the already large drifts around the buildings and created several nice snow sculptures in the yard.

Late in the afternoon skies started to clear and temperature started down as did the wind chill.
By 8pm you could see the moon and Venus off to the SW. Went out at 1030pm but only stars out no aurora and visibility was up to 6 miles in mist drifting snow, wsw at 14mph -20F.

Monday March 2
Today it is bright sunshine and very light to calm winds with unlimited visibility, and even though it is -28F you can feel the heat from the bright sun.

Did the monthly river ice check today and the ice is now at 47 inches.

March 2-3
After a long spell of cloudy or stormy weather the clear skies during the night allowed for star gazing and even a few aurora were out. I was out most of the night and the best shots were taken just after 2 AM, even then they only lasted about 20 minutes then faded away for the night.

March 4
Another beautiful day with lots of bright sunshine and light winds. Nice weather continued into the night and I spent several hours out side again enjoying the northern lights. From mid-night to around 4:30 AM we had some of the best aurora activity that we have had in weeks.