photo #8506461

Nancy Esworthy, sister of Kitty McCoy (Cloud Appreciation Society Member 52,344), was sipping coffee on her deck near Denver, Colorado, US one hot July morning when she saw what looked like a giant waterfall dropping from an Altocumulus cloud.The streaks, known as virga, or sometimes fallstreaks, are precipitation falling from a cloud that evaporates or sublimates before reaching the ground. Since it never touches down, we wouldn’t actually even refer to this falling water as precipitation. Virga appear when the air beneath the cloud is warm enough and/or dry enough for the falling droplets or ice crystals to turn into water vapour before they land. Virga tends to hang from the base of a cloud at a slant, due to the action of the winds. The straight, vertical drop of Nancy’s virga is rare. It indicates a still morning with little wind right up to the elevation of the cloud. You can finish your coffee in peace, Nancy. There’s no chance of this waterfall ever getting close enough to drench your sun deck.