This is the 10218th most frequent Japanese word.
降ら
"降ら" is a conjugated form of the verb "降る," meaning "to fall" (such as rain or snow).
In this sentence, '降ら' is used to describe the rain falling from the sky, indicating weather conditions.
雨が降らないと畑が乾いてしまう。
If it doesn't rain, the fields will dry up.
Here, '降ら' refers to snow falling, again related to weather phenomena.
雪が降らない冬は珍しいです。
A winter without snow is unusual.
In this usage, '降ら' conveys the act of descending or coming down from a higher position, applied metaphorically to the angel.