I would agree tha a motorcycle type helmet as discussed in this article would offer better protection, and they are not designed to split or crack open risking penetration from what I read there.
This from Wikipedia regarding ski helmets is quite depressing if true. They are only tested to 14 MPH?! and haven't reduced fatalaties:
While helmets are effective at preventing or reducing minor injuries, they have not been shown to reduce the number of fatalities despite the fact that as many as 40% of skiers and snowboarders wear helmets. "There is no evidence they reduce fatalities," according to Dr. Jasper Shealy. "We are up to 40 percent usage but there has been no change in fatalities in a 10-year period."
Helmets are tested for effectiveness at about 14 mph (23 km/h), but the typical maximum speed of skiers and snowboarders is approximately twice that speed, with some participants going much faster. At such speeds, impact with a fixed object is likely to be fatal regardless of helmet use. By contrast, in an impact with icy snow wearing a helmet can be the difference between a minor head injury and a significant or life-threatening head injury.
Moreover, helmet use may result in risk compensation i.e. skiers and snowboarders behaving less cautiously when they feel protected by a helmet. One study found that helmeted skiers tend to go faster and helmet-wearing has been associated with self-reports of more risky behavior other studies find that helmet use is not associated with self-reports of riskier behavior.
Edited by halifaxf1fan, 01 January 2014 - 19:03.