An apparatus, comprising: a stall detection system (102, 202, 232a, 232b, 262a, 262b, 302, 332a, 332b, 362a, 362b) comprising an optical system coupled to a processing system; wherein the stall detection system (102, 202, 232a, 232b, 262a, 262b, 302, 332a, 332b, 362a, 362b) comprises: an optical transceiver; wherein the optical transceiver is configured to emit at least one light beam (112, 212, 242a, 242b, 272a, 272b, 312; 342a, 342b, 372a, 372b); optics optically coupled to the optical transceiver; a window; wherein the optics is configured to direct the at least one light beam through the window; and wherein the optical transceiver is configured to detect backscattered light of the at least one light beam; wherein the stall detection system is configured to detect an onset of a stall condition in at least one measurement region (214, 244a, 244b, 274a, 274b, 314, 342a, 342b, 374a, 374b), proximate to a foil (203, 233, 263, 303, 333, 363) of a vehicle (101, 201, 231, 261, 301, 331, 361), by characterizing a fluid (208, 238a, 238b, 268a, 268b, 308, 338a, 338b, 368a, 368b) flowing in the at least one measurement region (214, 244a, 244b, 274a, 274b, 314, 342a, 342b, 374a, 374b) proximate to the foil (203, 233, 263, 303, 333, 363) by characterizing the backscattered light from the at least one measurement region; and wherein, upon detecting the onset of the stall condition, the processing system is configured to perform at least one of: generating an alert, and causing an automatic pilot to cause the vehicle (101, 201, 231, 261, 301, 331, 361) to avoid or exit the stall condition. a stall detection system (102, 202, 232a, 232b, 262a, 262b, 302, 332a, 332b, 362a, 362b) comprising an optical system coupled to a processing system; wherein the stall detection system (102, 202, 232a, 232b, 262a, 262b, 302, 332a, 332b, 362a, 362b) comprises: an optical transceiver; wherein the optical transceiver is configured to emit at least one light beam (112, 212, 242a, 242b, 272a, 272b, 312; 342a, 342b, 372a, 372b); optics optically coupled to the optical transceiver; a window; wherein the optics is configured to direct the at least one light beam through the window; and wherein the optical transceiver is configured to detect backscattered light of the at least one light beam; an optical transceiver; wherein the optical transceiver is configured to emit at least one light beam (112, 212, 242a, 242b, 272a, 272b, 312; 342a, 342b, 372a, 372b); optics optically coupled to the optical transceiver; a window; wherein the optics is configured to direct the at least one light beam through the window; and wherein the optical transceiver is configured to detect backscattered light of the at least one light beam; wherein the stall detection system is configured to detect an onset of a stall condition in at least one measurement region (214, 244a, 244b, 274a, 274b, 314, 342a, 342b, 374a, 374b), proximate to a foil (203, 233, 263, 303, 333, 363) of a vehicle (101, 201, 231, 261, 301, 331, 361), by characterizing a fluid (208, 238a, 238b, 268a, 268b, 308, 338a, 338b, 368a, 368b) flowing in the at least one measurement region (214, 244a, 244b, 274a, 274b, 314, 342a, 342b, 374a, 374b) proximate to the foil (203, 233, 263, 303, 333, 363) by characterizing the backscattered light from the at least one measurement region; and wherein, upon detecting the onset of the stall condition, the processing system is configured to perform at least one of: generating an alert, and causing an automatic pilot to cause the vehicle (101, 201, 231, 261, 301, 331, 361) to avoid or exit the stall condition.