Suppose an asteroid of radious 50m strikes the earth surface,what could be the impact of such collis

supposing that an asteroid of 50m radius is moving towards the earth
so what would be the impact of such collision and
if possible how can be this situation avoided ?

It honestly could be a world wide extinction level event. Depending on where it hit anyways. If it hit the ocean there would be catastrophic waves with the potential of reaching hundreds of miles inland destroying everything in its path. Now if it hit land, even one the size of Manhattan the dust cloud alone would cover most if not all the Earth causing what would essentially be a nuclear winter lasting hundreds of years. No sun, no plant life, no plant life all other life dies off.