Ruapehu is a noisy volcano, showing signs of eruptions on a yearly basis. It is also a potentially very hazardous volcano as it produces abundant lahars and has the capacity to generate a catastrophic lahar if the crater lake at the summit were to be breached by an eruption. This is why Ruapehu is one of the most closely watched volcanoes in the world, with all of its vitals being monitored on a daily basis. GNS Science in New Zealand is reporting that Ruapehu is headed into a new heating cycle, citing the increase in lake water temperature from 16 to 22C since August - and that seems like evidence aplenty as it takes a decent amount of increasing heat coming from the volcano to warm up that much water by 6 degrees. Combine that with volcanic tremors and increased gas output, then it is pretty clear we have new magma working its way up the system. I'm sure GNS Science will be keeping a close eye on the volcano in the coming months, however so far they're keeping the warning level at one (signs of unrest).