Sydenham House

Owen Sound, Ontario, Canada 

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Live Weather

Click on the image above for a time-lapse movie of the past 24 hours.

Temperature

-10.6°C

Beaufort Scale

Calm

Comfort Level

Uncomfortably Cold

Barometer

Rising

Cloud Base

970

High
Temperature

-3.3°C 
at 1:40pm

Low
Temperature

-16.1°C 
at 5:10am

Peak 
Wind Gust

16km/hr 
at 2:48pm

Sunrise

7:32am

Sunset

5:40pm

Moonrise

4:07am

Moonset

12:36pm

Three-day Forecast

Links & Tools

Official Seven-Day Forecast

Snow Gauge (beta)

Snow Data Acquisition:  This is, perhaps, the only autonomous real-time snow gauge currently operating on the internet. It employs a Linksys WVC200 network camera pointed at a length of 2˝-inch PVC pipe painted fluorescent orange. The pipe is held upright by an outdoor umbrella stand with its sleeve painted orange to match the PVC pipe.

To facilitate the recording of data at night, a length of LED rope lights runs down the side of the pole. It is held about four inches out from it by a combination of plumbing fixtures and improvised standoffs. The lights are secured to an aluminum yardstick by wire ties. This maintains the lights in a straight line, blocks the glare of the lights from the camera, and acts as a means of visually verifying snow depth.

An image of the pipe is recorded every ten minutes and processed by RoboRealm software, which is designed to provide vision capabilities for robots. Each image is filtered in the software so that only the florescent orange part of the image is visible (see bottom images at right). The software then draws a line from the top of the fluorescent area to its bottom, and measures the length. This value is processed by an algorithm written in VBScript that translates image pixel data to real-world snow depth in centimeters. The data is written to a CSV file and used by Image Salsa weather image processing software, and another VBScript program, to import and compose the overlays on the weather image at the top of this page. Data is accurate to within 2.5 cm (one inch).

The time-stamped image above represents the latest good data recorded by the snow gauge. To be considered good data, the same value must result from two consecutive image reads ten minutes apart. The numbers in the top-right of the image represent (in pixels) 1) the length of the visible pole; 2) the distance from the bottom of the image to the bottom of the visible pole (also shown as the green dot); and, 3) the distance from the bottom of the image to the top of the visible pole.

Snow Gauge 2.0 December 12, 2009: This year a number of improvements, most notably the relocation of the gauge to the deck, which accomplished several things. First, it provided a less protected, and therefore more representative exposure to snowfall. In addition, it was found that the patio stones absorbed heat and snowcover would not be sustained like it is on the deck. Just as significantly, the move permitted the relocation of the camera to the south of the pole, which reduces glare from the sun and provides a more reliable image on sunny days.

But because we have no North-facing windows, it was necessary to build weatherproof enclosure and keep the camera temperature above rated operating specifications. This enclosure comprises a Coleman cooler to keep the snow off the device. I opted not to enclose it hermetically because of problems with condensation. Instead, I wound an electric water pipe antifreezing device around the bottom of the box. This should come on and warm the box sufficiently in cold weather – if it doesn’t melt the plastic sheath and catch fire first.

Protection from the wind and the heat from the camera transformer inside the box keeps the temperature in it about five degrees above ambient. The camera operating temperature is rated at zero degrees Celsius. Thanks to the moderating effect of Lake Huron , temperatures here sit at around five degrees below most of the time. It will be interesting to see how the camera fares this winter.

Among other refinements this year: Roborealm tweaking to include temporal modules that even out rapid changes in pixel intensity and several other minor adjustments. As a result, the image is more stable and there is less flickering of the readings.

The downfall this year, if there is one, will be the fluorescent paint used on the pole. This colour is good because it doesn’t occur in nature and is unlikely to crop up on the image during weird lighting conditions to cause interference. Last year there was significant fading – to the point that Roborealm had difficulty at the end isolating the ends of the pole. I have since read that ultraviolet light degrades fluorescent paint. I changed the paint manufacturer this year with the hope that it will mitigate the problem, but I can already see some signs of fading. Next year there will have to be significant experimentation with paint colours and brands – not a task I look forward to.

I will be enjoying my Snow Gauge from sunny Florida again this year, where I will be spending January and February sipping Mohitos on the beach. Have a good winter.

The pole stands about 10 feet from the camera unit. 

Sun is the camera's enemy. It produces glare and destabilizes the image on sunny days. To prevent this, the camera needs to face north, which makes the sun travel behind it and shine directly on the pole.