When the Atmospheric pressure drops below this

≡1.013 25 bar
≡101.325 kPa
≡1013.25 millibars (mbar, also mb) or hectopascals (hPa)
≡760 torr
≅1.033 227 452 799 886 kg-force/cm²
≅1.033 227 452 799 886 technical atmosphere
≅1033.227 452 799 886 cmâ??H2O, 4 °C [A]
≅406.782 461 732 2385 inâ??H2O, 4 °C [A]
≅760.001 mm-Hg, 0 °C, subject to revision as more precise measurements of mercuryâ??s density become available [B, C]
≅29.9213 in-Hg, 0 °C, subject to revision as more precise measurements of mercuryâ??s density become available [C]
≅14.695 948 775 5134 pounds-force per square inch (psi)
≅2116.216 623 673 94 pounds-force per square foot (psf)

I get depressed...