Destruction Ritual Spell

It is a quest activated after achieving level 90 Destruction by talking to Faralda in the College of Winterhold.

Background
When asked about training in Destruction, Faralda gives the Dragonborn a book titled "Power of the Elements" with a single page of vague directions to ruins in the northern area of Skyrim

 Northward, haunted northern coastline And south, Dwemer live and toil, A simple place, a shield from draft. At this stand wield mage's craft So fierce the sea will boil.

Windward Ruins
Travel to Windward Ruins, south-west of Dawnstar. In the ruins is a pedestal that, when activated, places the book onto itself. Casting a Fire spell at the pedestal ("at this stand wield mage's craft so fierce the sea will boil") will trigger another page of text to appear. This time giving slightly less vague directions to ruins in the south of Skyrim near the Throat of the World.

Under Greybeards' morning shadow At this northern watch, long lost Nirn's hoary Throat does scrape the sky. Here unleash a chilling cry And gild this stand with frost.

North Skybound Watch
Go to North Skybound Watch, on the south-eastern edge of the Throat of the World, south-east of Riverwood. If not already discovered, start at Helgen and head east. North Skybound Watch is located north of the road running between Helgen and Ivarstead. On the way from Helgen, there is a path on the left side of the road before the Falkreath Stormcloak Camp. Continue on this path, as North Skybound Watch is just beyond Orphan Rock. After placing the book, cast an ice spell at the pedestal, which reads, "here unleash a chilling cry and gild this stand with frost". Before picking the book back up. The next page directs the player to a location near Karthspire:

Over western river waters, By Karth bounded, south and north On mountains sits a humble crown. Sky's wrath on this stand bring forth To shake these snowcaps down.

Four Skull Lookout
Travel to Four Skull Lookout, east of The Lover Stone, just south of Karthwasten, north of Sky Haven Temple, right above Red Eagle Redoubt (if you haven't discovered it yet). Place the book and cast a shock spell at the pedestal ("sky's wrath on this stand bring forth to shake the snowcaps down").

Finally, take the book back and read it. This awards the Destruction spell Fire Storm and more text in the book, this time a grim-sounding message from Shalidor.

Rewards

 * Reading the completed book grants the Fire Storm spell.
 * The Blizzard and Lightning Storm Spell Tomes are now available for purchase from Faralda in the College of Winterhold valued at 3330 and 3454 septims each, respectively.

Bugs

 * Four Skulls Lookout pedestal may not activate, thus preventing the quest from being completed.
 * Reloading a previous quick save will fix this.