snow under
to give so much of something that it cannot be dealt with
The extra paperwork snowed me under during the last week.

[TahlilGaran] English Idioms Dictionary ▲

snow under
v.
1. To cover over with snow.
The doghouse was snowed under during the blizzard.
2. informal To give so much of something that it cannot be taken care of; to weigh down by so much of something that' you cannot do anything about it.
■ Usually used in the passive.
The factory received so many orders that it was snowed under with work.
The disabled girl was snowed under with Christmas letters.

[TahlilGaran] English Idioms Dictionary ▲

snow someone under
to give so much of something that it cannot be dealt with
The extra paperwork snowed me under during the last week.

[TahlilGaran] English Idioms Dictionary ▲