What is the ruling on someone who experiences janabah in the wilderness, when the weather is cold and they have water, but can only perform wudu' without ghusl due to the cold weather? Is it permissible for them to perform tayammum, and is it sufficient to replace both ghusl and wudu'?

Whoever wakes up in a state of janabah before sunrise and is unable to perform ghusl due to the coldness of the water, has two situations:

1. If they find something to heat the water, they are obliged to do so, and perform ghusl even if the time for prayer has passed, because they have access to water and should not resort to tayammum. 2. If they do not find anything to heat the water and fear harm from using cold water, they should perform tayammum, and ablution is not required, as tayammum is sufficient to remove both major and minor ritual impurity. Tayammum is permissible in this situation based on the hadith of Amr ibn al-Aas during the Battle of Dhat al-Salasil.