Although another catastrophic eruption at Yellowstone is possible, scientists are not convinced that one will ever happen. The rhyolite magma chamber beneath Yellowstone is only 5-15% molten (the rest is solidified but still hot), so it is unclear if there is even enough magma beneath the caldera to feed an eruption.

Will there be warning before Yellowstone erupts?

Most scientists think that the buildup preceding a catastrophic eruption would be detectable for weeks and perhaps months to years. ... As at many caldera systems around the world, small earthquakes, ground uplift and subsidence, and gas releases at Yellowstone are commonplace events and do not reflect impending eruptions.

Can a volcano just erupt without any warning at all?

Most volcanoes provide warnings before an eruption. ... Steam-blast eruptions, however, can occur with little or no warning as superheated water flashes to steam. Notable precursors to an eruption might include: An increase in the frequency and intensity of felt earthquakes.