Physics of an hypothetical animal attack (orca ramming through sea ice) Question: Could an aquatic animal weighing 5,000 kg and traveling at 55 km/hr break through solid 11cm-thick ice?
Context: I am writing a story and want the physics to be as accurate as possible. I'd like to describe an animal attack where a creature, approximately the size and strength of an orca, rams through the ice beneath an ice fishing hut. I imagine the creature swimming straight upwards, perpendicular to the ice. However, I will not use this as a plot device if it physically unrealistic.
Please presume the ice has a 20 cm diameter hole drilled into it. This is the hole used for ice fishing. The creature is aiming for that hole.
What I tried:
I know nothing of physics, but I did attempt to figure this out. I used an online impact force calculator. It suggests that the peak impact force is 76.389 kN. I just have no idea if that is enough to bust through ice from underneath.
I also have no idea if this impact would be too injurious to be a decent hunting strategy, but that's another question.
 A: I don't think the orca's nose is sharp enough to cut or broad enough to spread force out over a very large area, so the relevant "strength" number for the ice is just the total weight it can support. The internet suggests that 11cm of ice can safely hold a few people. This is probably a conservative estimate, so perhaps it takes 1000 or 10000 kg to break the ice. This corresponds to about 100 kN of force.
5000 kg moving at 15 m/s, subject to 100 kN of force, will take about 5 meters to come to a stop. I don't think ice can stretch 5 meters, and I don't think an orca's nose can squish 5 meters, so the ice will break.
A: I have no reference, and my memory of this is years old. So it isn't the most reliable. I don't know that I believe it myself.
Long ago I read about someone in the artic seeing killer whales through the ice. Since the ice was 3 feet thick they walked out on it to see them better. The killer whales began swimming up and slamming into the ice, trying to break the ice under him. When the ice began to crack, he went back to shore.
However, It sounds plausible that an animal that weighs $2 \space 1/2$ tons, and can butt really hard with its head and/or kick really hard with its tail can break through 4 inches of ice.
Some marine mammals can kick very hard. A large whale can kill a large sea lion by kicking  hard enough to launch it out of the water. Again no references.
