The word among ski devotees is that stellar crystal snowflakes create especially hazardous driving conditions.
A stellar crystal snowflake, one of 10 types of snowflakes that scientists have identified, may not be seen in the Willamette Valley again for years.
Stellar crystals are far more common - like hard-core skiers - in inland states such as Idaho, Utah or Colorado known for their powder.
What you're holding is a stellar crystal, a type of snowflake.
Stellar crystal snowflakes form in the lowest part of clouds.
"If you go colder still, you get really beautiful stellar crystals
. Those tend to form at about -15[degrees]C (5[degrees]F).
It is shown how the presence of large dendritic and stellar crystals
, of needles and of deposited minigraupels modifies strongly the snowflake asymmetry.
Surprisingly, it was observed that increasing wind speeds up to 8.0 m/s did not have a strong effect on the generation of fragments or broken branches of dendritic or stellar crystals.
In spite of these difficulties, which may explain the large standard deviations of the main snowflake parameters in Table 6, seven main types of snow element aggregates were selected : 1) aggregates with prevailing needle type crystals; 2) aggregates with prevailing sheaths; 3) small crystals (bullets, columns, small plates); 4) medium size snow crystals (large plates, crystals with sector like branches, small stellar crystals); 5) large dendritic and stellar crystals; 6) aggregates of small graupels (minigraupels) and spherocrystals; 7) aggregates of frozen or half-frozen drops.
e) Snowflakes with large dendritic and stellar crystals (Type 5) contained approximately the same mean number of crystals in one snowflake (13.1) as snowflakes with medium size crystals (Type 4 in Table 6).
The division is rooted in the prevailing presence of specific snow crystals in aggregates and contains the following six types of aggregated snowfall elements: Needles and sheaths; small columnar and plate crystals; medium size plate and stellar crystals; large dendritic and stellar crystals; aggregates of minigraupels and frozen drops; mixtures of large drops (often from melted snowflakes) and snow crystals.
More than 63% of snow crystal samples--each usually comprised of more than 100 crystals-- contained broken arms of dendritic and stellar crystals. These fragments were divided into one arm, two arm, and three arm elements classified as either dendritic or stellar.