“A fierce windstorm arose, and the waves were breaking over the boat, so that the boat was already being swamped.” (Mark 4:37, HCSB)
Mark uses vivid description to help his readers to understand the gravity of what happens as the disciples row across the Sea of Galilee at night. Everything is going just fine and then all of the sudden along comes a “fierce windstorm,” sweeping down the lake. Mark uses the word λαῖλαψ [lailaps] which is a very strong wind equivalent to hurricane strength or a strong squall. These kinds of winds can easily knock down a sailboat or swamp other types of boats. Mark uses the imperfect tense to describe the wave action, they “were breaking over the boat.” This is an indication of ongoing action, that the wind squall came and did not leave, but beat relentlessly against the boat. The result, as anyone who has spent any time on boats in a wind storm can attest, is that the boat was near to being swamped, which is to say, as the water washed into the boat, it began to take on water and sank lower and lower into the Sea. If the windstorm continued, the disciples and Jesus would have had been dumped into the Sea as the boat sunk. This was a very real possibility as the disciples, many of them expert boaters could attest.
This sudden wind squall was not unusual:
Luke’s “came down” shows that the storm fell suddenly from Mount Hermon down into the Jordan Valley and smote the Sea of Galilee violently at its depth of 682 feet below the Mediterranean Sea. The hot air at this depth draws the storm down with sudden power. These sudden storms continue to this day on the Sea of Galilee. [Robertson – Word Pictures in the New Testament]
So to sum up what we have on a dark and stormy night on the Sea of Galilee: We have the boat in the middle of the Sea [with possible other boats in the vicinity], a sudden very strong and dangerous windstorm, professional fishermen who know they are in danger, a boat that is going to be swamped and sunk by the waves; in short the disciples are in extremis and everyone is frightened. Jesus? He’s in the stern sleeping.
Whatever else one can say about this incident on a dark night in the middle of the Sea of Galilee, Jesus is taking a fundamentally different approach to matters from the disciples. What does he know that they do not?