Syfy's "Sharknado 2: The Second One," was watched by 3.9 million people when it debuted Wednesday night, the network said, citing Nielsen ratings.
In the important 18-to-49 viewer demographic, the TV movie was watched by 1.6 million people.
Nielsen said "Sharknado 2: The Second One" also topped its Nielsen Twitter TV Ratings for the night with 581,000 tweets written by 188,000 unique authors and seen by 5.5 million people, generating 67.2 million Twitter TV impressions.
The TV audience grew meaningfully from the original, which premiered in July 2013 to just 1.4 million viewers. The first "Sharknado" also generated significant social media buzz, peaking at 5,000 tweets per minute, which helped generate viewership for the second and third airings, with the second airing of "Sharknado" watched by 1.9 million people and the third showing crossing the 2 million mark.
Syfy has already approved a third move in the franchise.
Syfy went on a marketing blitz ahead of the premiere of "Sharknado 2," with a campaign the network called a "category 5 marketing storm." Promotions included a book, "How to Survive a Sharknado and Other Unnatural Disasters," and a video game tied to the sequel. Syfy also got support from Subway, whose spokesman Jared Fogle made a cameo in the movie.
But Amobee, a mobile ad tech company, said celebrities didn't spontaneously talk about the sequel in social media at the same level as a year ago.
Of course, those starring in the movie, like Ian Ziering, and involved with Syfy or other programs at parent NBC Universal, were tweeting away.
Actor Wil Wheaton, who has a show on Syfy, was also active.
If Tara Reid doesn't end this movie with a chainsaw for a hand, I don't even know why we got out of bed today. #Sharknado2— Wil Wheaton (@wilw) July 31, 2014
But celebrity chatter outside of that was limited, according to Amobee.
As has become the norm around event-like programming, brands attempted to become part of the conversation.
Subway was the most active and saw the greatest social media impact, with 17,000 tweets mentioning the brand in the six hours leading up to, during and after the movie aired, according to Amobee.
Subway tweeted throughout the airing using the hashtag #cheesysubliners to insert sometimes witty comments.
Mr. Fogle tweeted "survival tips" and rewarded fans with swag. He also tweeted a proof-of-life photo to assure the world he survived the Sharknado.
There was an tweet from Lenovo, which posted a picture of a laptop in the ocean with a shark fin.
And the American Red Cross shared a Sharknado-themed Vine.