промерзать до дна

[Deep-one]

В зимний период река промерзает до дна.

[lesdn]

In winter the river freezes(is frozen) to the bottom

[tiina]

during the winter period the river freezes to the very bottom

[Полина Пак]

During winter time the river water freezes up to the bottom

[Franky]

"freezes up to the bottom"

Это что, значит, что дно на потолке находится?
:)))

[D-50]

..frozen all the way through

[Ken Golovin]

river freezes to the (stream) bed
IMO

[E-MALE]

freezes through down to the bottom

[10-4]

In wintertime, the stream/river freezes through its bed.

[gogolesque2]

during the winter, the river freezes solid through

during the winter, the river completely freezes