Boiling of cryogenic fluids is an important problem in superconductor technology, which becomes emergent in case an accidental, short-term and unsteady heating impulse appears. Here the process deviates from a standard scenario, approaching the crisis at lower heating. The present paper sheds light into the matter, aiming at the theoretical determination of the minimum critical heat flux required for the crisis to occur in the impulse mode. An analytical expression for the heat flux is derived and validated with the experiments on boiling in liquid nitrogen. Finally, a sensitivity study was performed looking at the influence of pressure, heater size and type of the fluid on the process. (C) 2017 Elsevier Ltd. All rights reserved.