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Admiral Fitzroy storm glass

Admiral Fitzroy storm glass

Admiral Fitzroy storm glass

I've been interested in the weather for as long as I can remember. I've always loved watching a thunderstorm approach, both by watching the sky as well as the radar.

For the last few years my real interest has been monitoring and attempting to predict the weather. I've built a couple of home brew weather stations, including attempts to predict the weather based on barometric pressure.

For Christmas this year, I got an Admiral Fitzroy storm glass. I have heard about these storm glasses before, but I never had one. Now I do!

According to the instructions the solution forms different types of crystals depending on the barometric pressure. Since barometric pressure has quite an influence on current and future weather conditions, in theory you can predict the weather based on the crystal formation inside the storm glass.

According to the instructions on the storm glass, you set the storm glass in a safe place away from direct sunlight or any air vents. The key is to have the temperature of the storm glass remain relatively the same so that only barometric pressure affects the crystal formation. I put mine in the dining room display case.

The instructions came with a very vague set of crystal descriptions to look for and the corresponding weather condition that they predict. The descriptions seemed more artistic rather than scientific. Some of the descriptions and corresponding weather predictions overlapped each other. Here is a table summarized from the instructions as well as what was printed on the storm glass itself.

Table 1: Storm glass states according to instructions
Storm glass condition Weather prediction
Clear liquid Clear skies, good weather
Cloudy liquid Rain coming soon
Crystals at the top of liquid Thunderstorms
Cloudy liquid with small stars  Thunderstorms
Large flakes of crystals Cloudy, snow in winter
Small stars floating on their own Snow in one or two days in winter
Crystals at the bottom of liquid Heavy air, or frost in the winter
Small spots floating in the liquid Fog or damp weather
Thread of crystals at top of liquid Windy

When I first got the storm glass a few weeks ago, I took it out of the box and followed the instructions to "reset" it since it may have become unstable in transportation from the factory. The instructions told me to gently heat the tube using a low setting on a hair dryer while gently tilting the tube back and forth. You have to be careful not to get the tube too hot or you will crack it and destroy it. I kept slowly heating it until the solution returned to clear as per the instructions. I then put it in its holder and put it away in the display case.

The storm glass remained a clear liquid for a few days. During this time the weather was indeed clear and sunny. A few days later, crystals began to form in the bottom of the tube. About 3 days later we got a fairly significant snow storm and then the weather remained cloudy with scattered flurries for about a week. Here is what the crystals looked like during this snow and cloudy weather.

Admiral Fitzroy storm glass crystal formation 3 days before a snow storm

Storm glass 3 days before a snow storm

I would describe these as large flaky crystals at the bottom of the liquid. According to the table, this would indicate "Cloudy, heavy air, frost, snow in winter". The weather did indeed produce snow, and when it was not snowing, it was cloudy. So far it does appear to be "predicting the weather".

However, the last two days it has been quite sunny and the large flaky crystals are still there in the bottom of the storm glass. I'm going to keep watching this storm glass over the next few months to see how accurate it is at predicting the weather.

I'll update this page with my findings.

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Page last updated: January 2, 2013.

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