The first week of February saw some cold weather with a teaser two-day warm spell where the highs approached 30 degrees Fahrenheit—just before the 7th, when a frigid air mass and high winds moved in. It was early in the month, the first Monday, and when I took a trip up to Lackawaxen, I noted that the air was still and the temperature was -7 degrees. Steam was coming off the water where open water was still present on the ice-laden Delaware River.

I had a cup of coffee at the Two Rivers Anglers Café near the Zane Gray boat launch, and by the time I was done, the morning sun had cleared the ridges and was shining on my face. As I squinted towards the sun, I saw multiple sparkling reflections that you might see when snow blows off a tree while looking sunward. The wind was calm and there were no precipitation-producing clouds nearby; there wasn’t a cloud in the sky.

This phenomenon is known as “diamond dust.” It typically forms during clear, still days, when the temperature is at least a few degrees below zero. Like snowflakes associated with storms, diamond dust needs a tiny nucleus of dust to form via deposition. Unlike a typical snowflake that forms inside a cloud, however, the ice crystal that forms diamond dust does so with the aid of very cold temperatures and some invisible moisture in the air. Gentle air currents cause these floating crystals to rise and move about, and they grow bigger and finally fall gently when they get too heavy. They are tiny and almost impossible to track, but I got lucky and spotted a couple on my car windshield.

Being close to the river probably helped put a bit more moisture in the clear air to enhance the formation of diamond dust. Meteorologists call them ice crystals; in aviation shorthand, they are called “IC” and are seen mostly at Arctic airport reports. There was more to see at the river this morning. Hoarfrost covered nearby bushes and distant trees on ridgelines alike. It is much more common along the Delaware and is formed when water vapor comes in contact with branches or other objects and forms long tendrils of ice. 

I have seen diamond dust only a few times, and it seems hard to appreciate glittering ice particles coming from a seemingly clear sky after having to shovel a lot more frozen precipitation from a storm a few days back, but there are gifts that nature brings, even in these cold times. This is one of her gifts.