When I played Oblivion I read a book called Immortal Blood which described how vampires were different in every realm of Tamriel. The book mentions the Volkihar specifically which I am happy about. There is one thing that caught my attention when I remembered this book. The conversation between the people of the book mention an ability of the Volkihar vampire which we cannot do in Skyrim.
The Volkihar vampire has the ability to move though ice without breaking the ice. The vampire would travel though the ice of a frozen lake to sneak up on their enemy.
The following is from the book "Immortal Blood" enjoy:
To my surprise, he returned the smile, though it was more of a grimace. "When tracking your prey, you adapt their habits."
The next day, he did return with more questions, these ones very specific. He wanted to know about the vampires of eastern Skyrim. I told him about the most powerful tribe, the Volkihar, paranoid and cruel, whose very breath could freeze their victims' blood in the veins. I explained to him how they lived beneath the ice of remote and haunted lakes, never venturing into the world of men except to feed.
Movarth Piquine listened carefully, and asked more questions into the night, until at last he was ready to leave.
"I will not see you for a few days," he said. "But I will return, and tell you how helpful your information has been."
True to his word, the man returned to my chapel shortly after midnight four days later. There was a fresh scar on his cheek, but he was smiling that grim but satisfied smile of his.
"Your advice helped me very much," he said. "But you should know that the Volkihar have an additional ability you didn't mention. They can reach through the ice of their lakes without breaking it. It was quite a nasty surprise, being grabbed from below without any warning."
"How remarkable," I said with a laugh. "And terrifying. You're lucky you survived."
This book is a good read, should you find it. The vampires from other realms are also very interesting. Being able to walk on water is nice but it would be cool to phase though ice to sneak up on an unsuspecting foe. Not very many frozen lakes in Skyrim though. The book also mentions the Volkihar living "beneath the ice of remote and haunted lakes." I guess they live in a castle too?