The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note of any observations you have made of the world around you. Rain, sun, wind...insects, birds, flowers...meteorites, rocks...seasonal changes...all are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located. Each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.February 6, 2014
During the past week in the maritime Pacific Northwest, a cold weather system has slid onto the area, blown here from inland Canada by north winds. We get these now and again in winter as brief chilly interludes in our usually mild climate. This one has lasted long enough for the humidity to plunge, so what was frosty earlier is now frozen and dry. The red Cotoneaster berries in my backyard changed from plump lightly frosted bunches into small frozen nuggets on the ground. Nevertheless, still very popular with the winter Robins.
(All photos by me. In Lightbox...click to enlarge)
As the days passed, it got colder. Standing water began to freeze in cool patterns.
As this cold air mass remains in the area, the air gets dryer than we usually see it in this seaside climate. Cold air can't hold as much moisture. The dew point (see the green line in the graph above) has fallen into the single digits, meaning it would have to get much much colder for that little moisture to condense out and freeze. So we aren't getting frost. Instead, the moisture in the soil and tender vegetation is freezing solid. There's no official or standard definition for it, but these conditions - below 28ºF or 25ºF for 4 or 6 or 8 hours - would be considered a "hard freeze" (to be distinguished from a "deep freeze" which has an even looser definition, depending on the area, eg. below -20ºF in Minnesota or below 40ºF in Florida, lol).
Now ice crystallizes and expands, pushing up the dirt, an effect known as "frost heave."
The wildlife in the moderate maritime Northwest has it far far easier than in much of the country, but even here, when it gets cold like this, they need shelter, water and food. I bring my hummingbird feeder in at night, and switch out the fluid during the day if ice begins to form at the top. Ar first light I put out the feeders. The flock of Robins in my backyard are chowing down on the Cotoneaster and Viburnum berries.
What's the water like outside where you live today? What's going on in nature on this winter's day in your backyard?
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WEATHER UPDATE: 9 pm, Feb 7
Since I queued this Bucket 24 hours ago, we had a shift in wind, with southerly breezy conditions sweeping in some damper air this morning. The dew point rose dramatically to 17ºF, with air temps hovering at the freezing point. Then this afternoon the wind swung around again. Northerly winds, now 21 knots, have cooled and dried the air. Here's the current temp graph. Notice that the dew point has dropped again. A chilly night in store tonight, below freezing. Brrr.