Alas, April is supposed to be the month of rain. We've gotten it — it's just been the frozen variety.

Snow is historically a rare episode after April 10. Mild days with occasional rain or snow prepare the fields for new crops and begins the greening of our landscape. Rain usually comes in the form of showers, but we can have it in unsettled weather such as thunderstorms and tornadoes.

We can live contentedly with April moisture knowing it is an essential part of spring, transforming and stimulating season that ordinarily should be growing better day by day. We can only hope.

Rain helps the snowbanks disappear, melts the ice on lakes more quickly, greens-up lawns, helps many woodland wildflowers come into bloom and makes deciduous trees begin to leaf out.

Thanks to the rain and snow, and evaporation, our water recycles again and again. Today we may brush our teeth with water that the dinosaurs drank. No kidding. That is interesting to think about while watching the moisture we are witnessing.

When we get the rain — and we will — it will come fast. Typical raindrops fall a bit faster than 600 feet per minute (about 7 mph) through still air. The size of the raindrop and movement of air will affect the speed, but think about some of those large raindrops that hit with a thud. Some fall at 15 to 20 mph.

The popular image of a raindrop is that of a completely spherical object or miniature liquid pear, symmetrically bulging at the bottom and coming to a point at the top. However, high speed photographs of raindrops nearing the earth show them to be flattened at the bottom with a mushroom shaped top.

As a raindrop falls through the air, the air resistance flattens the bottom of the drop and makes the droplet bulge on top.

An inch of rain is a lot of water. Quantitatively, a coating of an inch of rain over an acre of surface would mean 27,143 gallons of water, weighing 226,512 pounds.

No wonder our yard has had a different feel to my feet when I've walked a short distance from the backdoor out to the rain gauge soon after a heavy downpour.

Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.