Snownado

Mediterranean nations including Greece and Turkey were treated to a thick layer of snow earlier this year, which is rare enough as it is — but the storm system even triggered a "snownado." Also called snow devils, these rare funnels of the white stuff occur under certain conditions involving wind shear over snow cover, according to the World Meteorological Organization.

They do come from above — not extraterrestrials, but tiny crystals of ice hanging in the atmosphere. Ice is very thin, shaped like plates with hexagonal faces. When ice drifts down through the air, it falls close to horizontally. At the top and bottom are the faces with more area. Ice is very reflective, so when light hits those wider faces, it bounces around and reflects off more ice crystals.

That means we get these vertically stacked mirrors floating in the atmosphere. The light hitting it gets reflected up and up (or down and down, depending on the source), and becomes a radiant column in the sky.

Light can come from the sun, moon, cities, street lights — any strong light source.

Torrential rain from an atmospheric river triggered massive flooding in southern British Columbia and far northwestern Washington state. Abbotsford, British Columbia, and Sumas, Lynden and Ferndale, Washington, were among the towns that experienced at least some flooding.

Landslides cut off all exit routes out of the town of Hope, B.C., and left the Port of Vancouver cut off from inland areas. Parts of Highway 5 – known as the Coquihalla Highway – collapsed. Four people were killed in a landslide on Highway 99 south of Lillooet, B.C.

November was the wettest month on record in Bellingham, Washington (14.57 inches), and the second-wettest month in Vancouver, B.C. (12.3 inches).

Perhaps most stunning was aerial footage of the British Columbia flood zone after a light snow had fallen.

There will be more from British Columbia and the Pacific Northwest later in the countdown.

Virga is ghostly precipitation that never makes it to the ground. When the air beneath a cloud is very dry, precipitation falling through it evaporates before reaching Earth’s surface. What’s left are feathery streaks extending from the cloud’s base, capturing the path the rain or ice took before becoming water vapor. The evaporation process takes a lot of energy out of the surrounding air and causes it to cool. That cold air may then sink very quickly and dump a dangerously concentrated parcel of air and water/hail in a microburst.

But for the most part, virga is a visual effect. It shows up on radar as a typical rain or snow shower, but there’s no evidence of that at the surface. Great storms could be raging above your head, but the only trace you’ll see are the thin wisps of virga drifting through the sky.

The way these woolly growths formed had puzzled scientists since 1918, but we know the culprit now — it’s a fungus!

The fungus grows on dead tree bark, and when ice starts to form along its surface, the fungus releases chemicals that shape it into the distinctive narrow strands. Those chemicals also prevent the small, thin ice crystals from growing into larger ones and keep the hairy texture structured. Hair ice can stay in place for days in the right conditions, but often it forms in the cooler temperatures of night and melts away in the morning.

The July 29 outbreak spawned 14 tornadoes in Pennsylvania and six in New Jersey, including an EF3 tornado in the northeast Philadelphia suburbs.

Another seven tornadoes were spawned in eastern Pennsylvania and New Jersey as the remnant of former Hurricane Ida swept through. That included an EF3 tornado in Mullica Hill, New Jersey's first F/EF3 tornado in 31 years.

In October, 13 tornadoes touched down in western Pennsylvania on Oct. 15, 16 and 21. That pushed the state's 2021 tornado tally to 44, second-most of any year, according to the National Weather Service.

As of the time this article was published, 13 tornadoes were confirmed in New Jersey in 2021, according to the state's climatology office. That's the second-most in any year dating to 1950, behind only 1989's 19 Garden State tornadoes. The state averaged one to two tornadoes a year from 2001 through 2020.

One of these tornadoes was deadly – an EF2 tornado that downed a tree on a home in the northwest Philadelphia suburbs.

Since 1950, the majority of these violent tornadoes have happened from spring into early summer. The Newnan, Georgia, tornado on March 25 was the year's first EF4 tornado.

The only other two violent tornadoes in 2021 happened in December.

One of those tore across parts of Kentucky on Dec. 10. EF4 damage was found in the devastated community of Mayfield, with estimated winds of 190 mph and a damage path of 166 miles.

Another EF4 tornado spawned from the same supercell thunderstorm tore along an 80-mile path from far northeastern Arkansas across the Missouri Bootheel into extreme western Tennessee.

It was the deadliest U.S. tornado outbreak in 10 years, with at least 92 lives lost, 77 in Kentucky.

There were stories of survival, including two Kentucky sheriff's deputies who, after a very close call of their own, rescued a girl.

(MORE: Tornado Outbreak Recap)

Dust devils form in an upward motion from the ground to the sky. They are short-lived whirlwinds because cold air eventually gets pulled in. Dust devils can become tornadoes when a storm's updraft moves over the the existing ground circulation