The Rangipo Desert receives of rainfall per year, but resembles a desert because of its location on the volcanic plateau adjacently east of Ruapehu, a poor soil quality and drying winds, and also due to the mass sterilisation of seeds during a series of violent eruptions, particularly ignimbrite flows about 20,000 years ago. The vegetation is low and sparse, consisting of mainly tussock and snow grasses. The headwaters of many small streams, which later turn into large rivers, gouge deep serrated valleys through the unconsolidated ash and pumice-rich earth. The climate here is harsh and alpine, with close to 270 ground frosts per year in comparison with less than 30 in the coastal regions of Hawke's Bay, to the east. Heavy snowfalls - rarely seen in the rest of the island - are also a common occurrence in winter. Trampers and climbers in the area should be mindful of the extreme chill effect of the cold south wind which can produce wind chill factors lowering the temperature below 0°c (32°F) for days on end.