What was the purpose of the storm?

[ToshoftheWuffingas]

I posted this at TORC but I thought I would give the non-Torcers a chance to have a nibble at it too.

In the Redhorn Pass, Boromir says that Sauron can raise storms on his borders and we see one such in The Two Towers. It drenches Frodo and Sam as they pick their way out of the Emyn Muill but then heads out across the Vale of Rohan to finish at Helm's Deep. Merry And Pippin see it at a distance when Treebeard is attacking Orthanc so it was not aimed at Saruman. Gandalf describes it as a very storm of Mordor before he leaves Théoden. The Professor takes a few pains to use the storm at several points of the story so it is not an idle piece of background.
Now I can see sound literary grounds for the storm; it makes Frodo and Sam's journey that much more miserable and hearing the shriek of the Nazgûl on the storm makes a good Gothick touch; likewise it provides a similarly dramatic backdrop to Helm's Deep. Another literary reason is that it helps the reader to subconsciously keep track of the different timelines.

What puzzles me though is what purpose Sauron would raise such a storm. Powerful though he is I would guess a storm of that size is a drain on his powers. He will have no inkling of Théoden riding to Helm's Deep before he raises it; he has no need to affect the battle of the Fords of Isen and though he just might be aware of Saruman's capture of hobbits when the storm leaves his borders, it doesn't seem aimed at Saruman. So, any ideas anyone for the internal justification for the storm?

[Holbytla]

I always viewed the storm as a means of protecting his border against intrusion.

He knew the ring was abroad and feared an attack, but as was stated somewhere, he couldn't watch all ways at the same time.

Had it not been for the elven rope....who knows?

I also suspect that the Nazgûl sensed the presence of the ring in that area, and perhaps the storm was made to keep whomever in check while the Nazgûl searched.

[BrianIsSmilingAtYou]

Sauron thought of the eagle plot, even if Tolkien didn't.

BrianIs AtYou

[Frelga]

I was going to say that Sauron was just a nasty git like that, but I think Brian got it.

[BrianIsSmilingAtYou]

On a more serious note, the storm(s) had a very specific purpose, in my view. The following discussion focuses primarily on the later storm that hits Gondor, but I think that the reasons may be similar, and there is more detail on the effects of that storm. The earlier storm may have been a warm-up, and may also have had similar motivations as explained below. From a literary standpoint, the latter storm had a more direct impact on the plot as shown below. The earlier storm may have served the literary purpose of establishing Sauron's propensity to produce storms, so that it didn't seem pulled out of a hat.

The storm that struck during the attack on Gondor enabled the large armies of orcs and trolls to abide traveling in daytime by blocking out the sun.

Its effect was also felt as a hindrance to others, such as the Woses, who helped the Rohirrim reluctantly, in the hope that they would help dispel the storm. The Woses know that day has come "in the sky-fields" above the darkness of the storm, and ask that the Rohirrim " drive away bad air and darkness with bright iron!"

The second storm also seemed very much like a deliberate sequel to the first, and part of the same plan, so I don't think that they can really be considered separately.

Mordor was in a perpetual haze (at least on the plain of Gorgoroth, if not around Lake Nurnen) due to the smoke of Orodruin, but there was no guarantee of cover outside the wall of the Ephel Dúath and the Ered Lithui.

Sauron was moving beyond the need for mere sorties at night with his lesser minions, and while the men under his sway did not mind the sun, this was not true of most of his minions, other than the great Uruks and Olog-hai.

Even they probably preferred darkness.

The end of Chapter V of Book V in ROTK, The Ride of the Rohirrim, sums it up well, when the darkness broke early:

His [Théoden's] golden shield was uncovered, and lo! it shone like an image of the Sun, and the grass flamed into green about the white feet of this steed. For morning came, morning and a wind from the sea; and darkness was removed, and the hosts of Mordor wailed, and terror took them, and they fled, and died, and the hoofs of wrath ran over them.
...

[Chapter 6, which follows, continues]

But it was no orc-chieftan or brigand than led the assault upon Gondor. The darkness was breaking too soon, before the date that his Master had set for it...

This does not mean that the orcs and trolls simply fled (though ordinary trolls would be useless in sunlight), but that they were not at full strength in the battle, and the main part now fell to the Haradrim and other men in Sauron's army, Easterlings and Southrons.

Later in chapter 6, after Aragorn unfurls his standard, and the men of Gondor redouble their efforts, the effect of the sun is emphasized:

East rode the knights of Dol Amroth driving the enemy before them: troll-men and Variags and orcs that hated the sunlight.

This is in contrast to the statement at the battle of Helm's Deep about the first storm, that "these creatures of Isengard, these half-orcs and goblin-men that the foul craft of Saruman has bred, they will not quail at the sun." But this was not Sauron's interest; the first storm was simply a necessary prelude to the larger storm to follow.

BrianIs AtYou

PS

I have read somewhere the suggestion that the breaking of the storm may have been an intervention of the Valar or Eru; I do not remember where.

[Edited to add note about discussion of later storm vs earlier storm, fix spelling]

[Holbytla]

Ooops.
Looks like I got the wrong storm.
Although supposedly the pall that Sauron created was no weather of the world.

[ToshoftheWuffingas]

Thanks for that exposition, Brian although I consider the Dawnless Day aka the Murk of Mordor a different matter. That was a pall of volcanic ash perhaps directed by a wind that Sauron conjured. As your post shows it is worthy of a thread all by itself and it fulfills many functions both literary - I remember the impact it made on me as a reader even after many years - and also internally as you point out. I could certainly talk about that separately.
The storm I mention is a conventional one and it seems to be aimed at Helms Deep and I can't fathom its purpose.

[Alatar]

As an aside...

I quite liked that PJ & Co made Saruman the controller of the storm on Caradhras, not Sauron. It always seemed a little implausible to me that Sauron could send those Magic Wargs and a Storm right onto the Fellowship.

[Crucifer]

Sauron wasn't wuite sure where the ring was, was he? Only Saruman, watching the pass, whould have seen Gandalf and the halflings and tried to stop them.

[Alatar]

Well, in the book its clearly stated as Gandalf's opinion that the storm was sent by Sauron. PJ's Saruman was working much more closely with Sauron than JRRT's.