8 inches of snow this weekend; was it worse 'back in my day'?

The National Weather Service has issued a winter storm watch that could drop several inches of snow on the suburbs from Saturday evening into Sunday evening and bring dangerous winds Sunday

The weather service warns of snow "in excess of 8 inches" especially along and south of I-88.

"Periods of snow could lead to reduced visibility under a mile and snow-covered roads, making for very hazardous travel conditions," the watch says.

Northeasterly winds will increase Sunday, leading to blowing and drifting snow.

"Near-blizzard conditions are possible in open areas and along the immediate lakefront," the service says.

Wind gusts along the shore could approach 40 mph Sunday, the service says.

'Back in my day'

It's almost a universal cliché that Grandpa will look out the window at a storm and sneer that the snow was deeper back in his day.

U.S. record books will show, in most cases, that winter storms drop more snow now.

"People do have a tendency to remember storms as bigger than they were," said Matt Kelsch, a hydrometeorological instructor at the University Corporation for Atmospheric Research in Boulder, Colorado.

Before a humbled Grandpa is sent off to sit in the corner and watch television, however, Kelsch has something to add: The snow might have been deeper in the old days regardless of what the record books say.

This doesn't mean the amount of space an inch takes up on a ruler has changed.

What's changed is the way snow is measured in the U.S., and that means the figures today could be 15 to 20 percent higher than they were decades ago, said Kelsch, who works for UCAR's Comet program developing training materials for universities and the National Weather Service.

Today, snow is measured on a white board every six hours, Kelsch said by telephone. After the depth is recorded, the board is wiped clean and the snow is allowed to pile up again. Years ago, weather watchers would check once every 12 to 24 hours. The change may seem small but it can make a big difference, he said.

Old method

Snow on the ground can get compacted, and if the earth is warm, it can melt. So if someone waits a day to measure it, the total could be lower than it really was.

Snow also has various consistencies that can make a difference. Wet snow is heavy and settles; fluffy snow is light and puffs up more.

"The point is, as taken as a whole, the methodology used today would give you more snow now than it did before," Kelsch said.

Airports began using the six-hour method in the 1950s. Other weather observers started later.

New York's Central Park is one of the places where the method didn't come into practice until the 1990s. The park is often considered the benchmark for information in the region because people have been watching the weather there since 1868.

Making comparisons

Climate researchers are aware of the problem of making comparisons, and some don't bother to use snowfall totals because it's so hard to reconcile what happened this week with what happened 75 years ago.

The great blizzard of 1888, for instance, crippled New York City yet its official snow total is listed at 21 inches, said Kelsch, who grew up on Long Island.

"If you look at photographs, the amount of snow in the streets of New York appears to be greater than anything we have had since," Kelsch said.

So can the "Snowpocalypse" of a few years back be measured against the blizzard of 1888? Or the 19th century storm against the 9.8 inches that fell in Central Park earlier this week?

Probably not.

Whenever a storm has just buried a city and people debate where its snowfall fits in the overall record, Kelsch said he wonders "if people really know what really goes into that."

Grandpa, it turns out, may have been right.

To contact the reporter on this story: Brian K. Sullivan in Boston at bsullivan10bloomberg.net To contact the editors responsible for this story: David Marino at dmarino4bloomberg.net Charlotte Porter, David Papadopoulos