biology
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies.Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Thank you for your feedback
Our editors will review what you’ve submitted and determine whether to revise the article.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies.Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Written and fact-checked by
The Editors of Encyclopaedia Britannica
red snow, snow or ice surfaces, usually overlying soil on mountains, that are coloured by algae such as Chlamydomonas or Raphidonema. During seasons when there is little sunlight and temperatures are below the freezing point, the algae are dormant.
This article was most recently revised and updated by Amy Tikkanen.