Just got done reading this book. Its an amazing account of survival in the most extreme circumstances. And something strange they encounter.
https://www.amazon.com/Long-Walk-True-Story-Freedom/dp/149302261X/ref=sr_1_2?ie=UTF8&qid=1540571957&sr=8-2&keywords=The+long+walk&dpID=51CUfy8StiL&preST=_SY291_BO1,204,203,200_QL40_&dpSrc=srch
*spoiler alert*
Basically its about a Polish Cavalry officer that is imprisoned by the Soviets during WW2. He is sentenced to 25 years hard labor in a gulag in Siberia. Just getting to the camp many perish, the camp is a logging camp on the Lena river. He escapes with several others and they head due south through the tiaga, then the Gobi and finally the Himalayas.
They encounter two creatures in the Himalayas. And the encounter is not fleeting.