rhyme - Riddle Poem: I come from a cloud

Who or what is this poem referring to?

I come from a cloud.
Some long streaks of light
And a glowing shroud.
But now out of sight.

Seen in the summer,
Despite my nickname.
Many deaths occurred,
But I'm not to blame.

Answer

I think it's:

Halley's comet

I come from a cloud:

The article mentions that Halley's comet could have originated from the Oort Cloud if it was a long-period comet at once.

Some long streaks of light and a glowing shroud

This is the contrails and "shield" that develop in front and behind, respectively, of the comet itself.

But now out of sight.

Halley's comet passed at a relative speed of 70.56 km/s when it passed in 1910.

Seen in the summer, despite my nickname:

thanks to Geobit's advice, comets are normally referred to as "dirty snowballs".

Many deaths occurred, but I'm not to blame.

this site claims that Halley's comet was the cause of the Middle Ages plague, which killed many. Also, comets were seen as heralds of death in those times, as a simple Google search will show.

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Note from pacoverflow (since comments sometimes disappear):

Halley's comet is an acceptable answer. I was thinking about Comet Hale-Bopp and the Heaven's Gate cult. Hale-Bopp is interesting because it has three long streaks of light (tails) instead of the usual two that comets have.