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Category Archives: Phenomena
What is a flash flood?
A flood occurs when water flows into a region faster than it can be absorbed into the soil, stored in a lake or reservoir or removed in runoff or a waterway into a drainage basin.
A flash flood is a sudden local flood characterized by a great volume of water and a short duration. It occurs within minutes or hours of heavy rainfall or because of a sudden release of water from the breakup of an ice dam or constructed dam. Continue reading
What are pyrocumulus clouds?
A pyrocumulus cloud forms from rising air that results from intense heating of the surface by phenomena such as wildfires or volcanic eruptions. The fires that generate these clouds can be man-made or natural. A big fire produces strong upward moving air currents that carry water vapor and ash upward. The water vapor can condense on the ash forming cloud drops. The vigorous upward motions produce these pyrocumulus clouds that look similar to thunderstorm clouds, which also form due to strong upward moving air. Continue reading
Why are the cloud streamers behind jets different sizes?
The white condensation trails left behind jet aircraft are called contrails (condensation trails). Contrails usually form higher than 26,000 feet above the ground. Contrails form when hot, humid air from jet exhaust mixes with surrounding air of low water vapor content and low temperature. The clouds that form are similar to the cloud you see when you exhale in cold air and “see your breath.” Continue reading
Category: Phenomena
Tags Clouds, Human influences, Phenomena
Comments Off on Why are the cloud streamers behind jets different sizes?
Tags Clouds, Human influences, Phenomena
Comments Off on Why are the cloud streamers behind jets different sizes?
Why does it smell good after a rain?
Many times after a rain, there is a distinctive odor in the air — a sort of musky smell. This pleasant fragrance is most common in rains that follow a dry spell. If you are a gardener, you may find this smell similar to the smell you sense when you turn over your soil. Good organic soils contain bacteria. One bacterium that is abundant in damp warm soils is actinomycete. Continue reading
Category: Phenomena
Tags Phenomena, precipitation, rain
Comments Off on Why does it smell good after a rain?
Tags Phenomena, precipitation, rain
Comments Off on Why does it smell good after a rain?
How do large snowflakes form?
There are four basic shapes of ice crystals: the hexagonal plate, the needle, the column and the dendrite. The dendrites are hexagonal with elongated branches, or fingers, of ice; they most closely resemble what we think of as snowflakes. The temperature at which the crystal grows determines the particular shape. A snowflake is an individual ice crystal or an aggregate of ice crystals. Large snowflakes are aggregates of ice crystals. Continue reading
