Sublimation

by Eric Peterson

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A SNOWFLAKE IS A DELICATE LITTLE THING. BUT PUT BILLIONS OF THEM TOGETHER WITH A LITTLE WIND AND PRETTY QUICK THEY CEASE TO BE DELICATE LITTLE THINGS!

JUST IMAGINE HOW BIG A PILE OF SNOW WOULD BE CREATED IF ALL THE SNOW THAT FELL IN THE FIFTY MILES UPWIND OF HERE ALL WAS DEPOSITED IN THIS ROADBED.

WELL, THE FACT IS A BLOWING SNOWFLAKE HAS A VERY SHORT LIFETIME. RESEARCH INDICATES THAT A BLOWING SNOWFLAKE SELDOM MAKES IT MORE THAN THREE THOUSAND YARDS.

THE FARTHER THAT A SNOWFLAKE BLOWS, THE SMALLER IT GETS. THAT’S BECAUSE IT – AND HERE IS THE NEW WORD FOR TODAY – IT IS SUBLIMATING.

SUBLIMATION IS THE WORD WHICH DESCRIBES THE PHENOMENA WHERE A SOLID SKIPS THE LIQUID PHASE AND MOVES STRAIGHT TO A GAS, NEVER MELTING INTO A LIQUID. IN OTHER WORDS, ICE TURNS TO WATER VAPOR IN THE SUBLIMATION PROCESS.

THIS PROCESS ACCOUNTS FOR THE DISAPPEARANCE OF ABOUT EIGHTY PERCENT OF BLOWING SNOW. SO THE WATER THAT WAS IN A SNOWFLAKE TURNS INTO VAPOR AND IS CARRIED ON DOWNWIND TO MAKE A CLOUD OVER ILLINOIS RATHER THAN TO WIND UP IN A ROADBED, BEHIND A SNOWDRIFT OR IN YOUR DRIVEWAY.

FOR THE UNIVERSITY OF WYOMING COOPERATIVE EXTENSION SERVICE, I’M ERIC PETERSON.