<http://schema.org/alternativeHeadline>
"Weather data shows that this month's cold wave was brief compared to others that have occurred in the last forty years."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/climate-weather/stories/how-does-the-polar-vortex-measure-up-to-past-freezes>