Category Archives: weather

  It’s that time of year: mid-day in June is the time to watch for the circumhorizontal arc. The arc forms low in the sky when the Sun is high. I watched for it yesterday, but did not have a good … Continue reading →

  Advection fog is the name given to the fogs that form, usually in the summer, when warm moist air from the land flows offshore (is advected) over a much colder ocean. Simple books will claim that it is merely … Continue reading →

  A rip is stretch of fast-flowing and rough water. Much confusion arises from that simple definition: In the public’s mind, the only rip is the particular one that is often called a rip current, but, given its provenance, really should really … Continue reading →

  It may be spring in the valleys, but there is still snow in the mountains—and interesting snow at that.  Stu Heard sent me pictures from a foray that he and Holley Rubinsky made up Mt. Buchanan a week ago. … Continue reading →

  Yesterday, there was a halo around the Sun; this morning, the rain (or snow) began. These events were related. The earliest sign of an approaching mid-latitude storm is often a canopy of cirrus—a veil of ice crystals. While simple … Continue reading →

  Uncinus is Latin for hooked and when applied to cirrus—itself Latin for a lock of hair—it nicely characterizes the cloud, below: formally, it is cirrus uncinus. A familiar name for these clouds is fallstreaks, for they are streaks of ice … Continue reading →

  I last saw frost flowers bloom along the shore of Kootenay Lake five years ago. Since then, watching for these delights has been rather like searching for a rarely blooming wild orchid. Frost flowers bloom under a rather narrow … Continue reading →

  I don’t understand why I don’t see (cloud) billows as often around here as I have seen them elsewhere. These billows are formed in a thin atmospheric layer where the temperature and wind change markedly with height. The airflow … Continue reading →

  Frazil ice is a collection of loose, randomly oriented flakes of ice in water. Frazil resembles slush and has the appearance of being slightly oily when seen on the surface of water.  In a recent posting, it was noted that … Continue reading →