How deep is the snow?

It snowed in Tokyo again.
The Japan Meteorological Agency (JMA) announces how deep snow lays each hour. The snow depth in Tokyo was announced as "two centimeters" deep at noon today. But to be exact, the number here is how deep it gets in the Otemachi area of Tokyo, where the JMA building is located.
It was much deeper in Shinjuku and Shibuya, and of course it should've been deeper in Setagaya Ward in the west and Nerima Ward in the north.
Questions marks fly over many citizens when they hear the snow in Tokyo was only 2 cm deep!
We have to remember there's two ways to observing snow.
The first way snow is observed is by its depth. It's "how deep the snow is now." The local meteorological station has an observatory with a scale (the "snow scale"). Recently, laser beams and supersonic waves are used to read the depth automatically.
The second way is very primitive. The station places a clean board (the "snow board" = not the one you ride at ski hills!) outside and leave it there for 6 hours (or 12 hours) and measure how deep the snow gets. The data is "how deep the snow has fallen for the recent 6 (or 12) hours."
Warnings are issued according to the second type of data. Even though the snow quits to stop, the data of how deep the snow is (the first type of data) doesn't always change, because as snow falls on top of an older layer of snow, with its weight the snow gets pushed down, which won't help changing the data.
Today, the depth of snow in Tokyo was 2 cm for so long though it was snowing for hours. Hard to realize how snowy it was today just looking at these data inside buildings!!