Hypothermia and ice-related road accidents are by no means the only life-threatening conditions in very cold weather. A report from Moscow gives another sharp cause for anxiety.

According to a report in Flight International magazine, weather was a contributory factor in 16 of the 51 fatal air crashes in 1997, which resulted in 535 deaths. Only air crew error, which contributed to 32 crashes, was a greater risk factor.

In extremes of heat or cold, you can freeze, or suffer fatal respiratory ailments, or crash in car or plane. In Russia, however, another hazard has been identified: icicles. "In central Moscow, with so many slanting roofs, getting rid of icicles becomes the second most important task after maintaining heating systems," said Yelena Samsonova, who is an engineer with the Building Maintenance Office No 2. Last year, two Muscovites lost their lives to falling icicles, with another 50 injured.

Last week an order was signed to increase the numbers of city workers who inspect rooftops and hack off icicles that could pose a threat to passing pedestrians. "We put up barriers with `Dangerous Area' signs on them," Ms Samsonova said, "but people just walk through. Especially infuriating are those mothers who not only walk through the warning barriers themselves but take children with them. They are just no less than criminals."