No gas to cook top

You may be right about debris. We'll see. But here's where I get lost. The regulator is set by the spring pressure and the ambient atmospheric pressure. More pressure on the spring pushes down on the valve and opens it making for more gas flow output and more pressure. But when the spring is set in the first place it is done in conjunction with ambient atmospheric pressure on the diaphragm. At higher elevation, that atmospheric pressure is less and the valve moves a tad toward closed — like turning the spring screw a bit counter clockwise (which will also decrease output pressure). The regulator itself is not closed to the atmosphere, though the tank is. What am I missing? I do grasp that the oxygen changes and that influences the flame efficiency. Urged kids to tap the stove regulator. Don't know if they did. We will work on this in the week ahead, but it is difficult/impossible to diagnose an altitude issue at now a lower elevation!