Of all the weather related warnings that occur in Hawai´i, flash flood warnings are the most prevalent. This is due to two main factors: the amount of rain we get here in the Rainbow State and the steep, mountainous terrain. As each severe weather alert reminds us, it doesn’t have to be raining where you are for a flash flood to occur. The upper elevation slopes of these volcanic mountains get extraordinary amounts of rainfall, then the trickle of a stream and tiny waterfall you are splashing in becomes a raging gulley washer. And it was sunny there too! Conditions can change rapidly.
The volcanic rock that comprises the Hawai´ian islands is relatively brittle and easily erodes away. The deeply incised valleys of the windward sides of the islands attest to this. Those beautiful waterfalls along the Hana Highway exhibit the power of water to carve its way through the rock. There is nothing quite like going for a swim in a cool, freshwater pool with a waterfall cascading down around you. However, look in the bottom of the pools; those boulders weren’t put there by people. Use caution when swimming under waterfalls and be aware of what the weather is doing in the mountains upstream. As we say here at Hawai´i Revealed, “Know before you go”.
Being on the ground and researching the best areas to visit often puts us in danger’s way. We have numerous times been in the same areas where people have been swept away by flash floods. Sometimes folks get away with just a few bruises but other times it is far more serious. The emergency rescue crews are also put in danger when attempting these (usually) preventable incidents. We are all about finding your own adventure but we also encourage you to be as well informed as possible. Winter time brings the most rainfall but any rainstorm can trigger a flash flood. Be aware, have fun and be safe out there!