For full context, see here.
The sentence in question:
I already posted a fairly similar question here.
But I cant really find out how to apply the regularities lined out in the answers can be applied to なる here.
So basically, I dont know how と in 厳しい冷え込みとなった２５日朝 is used here. I also don't really know what to do with ほか in 滝つぼが一面凍りついたほか.
My attempt at translation:
"There was intense cooldown on the 25th morning, and one side of the waterfall basin froze over (ほか???) and concerning in the surroundings of the waterfall, there appeared icicles and the rocky area was dyed white."
To make this translation, I just jused "and" constructions to cover the parts I didnt understand, but I would definitely like to know how these parts work ^^