The term "atmospheric hardcore" isn't a widely accepted term,
but it is an accurate one (coined by some reviewer, somewhere),
describing a new-ish genre of extreme music that fuses mostly
hardcore-ish vocals with drawn-out songs featuring harder parts as
well as sparse, ambient/atmospheric quieter moments.
For some time this was more or less the domain of a single band,
that being Neurosis
while in recent years bands such as
Cult Of Luna
and others have come along, making this is a small but select genre.