| A | B |
|---|
| rugged | rough, uneven surface |
| musher | driver of a dogsled team |
| vowed | promised |
| checkpoint | place along a route where a check or count is made |
| volunteer | someone who helps free of charge |
| blizzard | long, heavy snowstorm with strong winds |
| whiteout | clouds over snow, leaving conditions that make it impossible to see |
| refuge | safe or covered place out of bad weather |
| burrowed | dug a hole like a small animal |
| experienced | having the knowledge or skill from having done a particular thing in the past |
| layover | a brief stop on a trip |
| squinted | looked with eyes partly open |
| courageous | having or showing courage, brave |
