Last month’s snowstorm in Washington DC failed to break records, in spite of the volume of snow that fell. There was a problem with the measurements at Reagan national airport where meteorologists had not used the approved measuring aid, the snowboard.
Snowboards are white to minimise snow melting on them, and they must be cleared at intervals to prevent packing or settling affecting the calculation. Snow measured as it piles up on the ground can give a distorted idea of the accumulation; the snowfall reading can give a lower amount than the correct figure. That is what seems to have happened last month at Washington.
But this is not the first time an instrument malfunction has affected extreme weather measurement. El Azizia, in Libya, held the record for hottest place on Earth for 90 years, after a blistering 58C (136.4F) was measured in 1922.
But a 2012 investigation from the World Meteorological Organisation ruled that “problematical instrumentation”, in the form of a potentially flawed thermometer, made the record invalid.
The problem is not always solved by better instruments. The traditional spinning anemometer measures wind speed at a single point; the highest speed ever measured with one was 253mph.
By contrast, Doppler radar can pick up the highest wind speed over a wide area. The highest radar windspeed is over 300 mph. But is it fair to compare this with earlier anemometer records?
Still, at least with the missing US snowboard the Washington meteorologists had a good excuse: they lost it in a snowdrift.
