Depends on the size of the rock. A small rock striking earth is one thing,
but a 1 Mile across Meteor is a Monster.
I just ran a program that gives the following data:
Size= 1 mile across
Density= medium (not ice, but not iron-nickel)
Angle of Impact= 45°
Strikes Surface of: Sedimentary rock
Crater Size(diameter) = 22km or 13.6 miles across.
Effects at 1,000 km (620 miles) distance from blast site would be at least an 8.2 Richter scale Earthquake which would occur 200 seconds after impact.
The fireball would be below the horizon, so, unless it was night time, you wouldn't see the flash. Ejecta would arrive, 1000 km away, in 494 seconds (about 8 minutes). It would create it's own wind of 22.5 mph, that is at 1,000 km distance. It would create a sound blast, at the 1,000 km distance of 73 db, which is like the sound of Semi-truck going by.
The good news, it's not quite large enough to shift Earth's orbit or axial rotation. Earth would retain 99.99% of it's original mass.
The bad news, 8.2 is a pretty big shake up, ask any Californians on here if they want to expereince an 8.2 on the richter scale. And this is at 620 miles away from the impact site. The meteor that made Meteor Crater was about 600 feet across, gives you some comparison of magnitude.
Here is a description of a 1.7 km wide meteor striking NYC:
At approximately 4:27 this morning EDT Asteroid 2004 Cyrus landed on New York City. Since the discovery of its trajectory and impending impact about one year ago the governments of the US and Canada have done their best to relocate the populations of areas within 500 miles of New York City. With the force of its blast estimated at 1,000,000,000,000 tons of TNT, the shockwave flattened buildings over much of New England and the Mid-Atlantic states. Firestorms are raging across the eastern United States as far as the Mississippi, creating a cloud of smoke and dust which will create life-threatening weather conditions worldwide. Predictions are for global cooling on the order of 4-8 degrees celsius (8-20 degrees Fahrenheit). Massive crop failures may lead to global starvation and hundreds of millions of additional deaths.
How can you plan for such an event?
If you knew a year in advance, then you could play Beverly Hillbillies and load up the truck. I would head south, as a 4 to 8 degree drop in global temperature is gonna be like a a mini ice age.
Even then, all surface water will be contaminated and undrinkable.
The human race will be thrust back in time, living like CaveMen to, at the very best, Middle Ages.
It's so easy, a caveman could do it
Pretty bleak outlook for this scenario.