Hi,  I know how disheartening it is to have a squash full of fruit suddenly wilt and collapse.     First look for any kink in the main growth of the plant stem.  This looks like a heavy plant and I wonder if it could have collapsed on itself.  
    Then,   I would look for signs of squash vine borer. This is an insect usually found in the East.  Yet, worth looking for:  Closely inspect the base of the vines and stems for single, tiny, reddish-brown eggs and wipe them off. If a borer does manage to hatch, you can tell by the appearance of a mass of frass (crumbly borer excrement) on the vine. You'll find the borer entry hole under the frass. Use a small, sharp knife to slit open the vine lengthwise at that point and remove the white larva. Mound soil up around the stem to encourage new rooting. The plant often survives if you catch the borer soon enough.

. And shade plant from hot sun.meanwhile keep a sharp eye out for insect eggs on your healthy squash vine.

There are also squash bugs. This insect sucks plant sap from stems and leaves causing collapse.  This link will tell you more about squash bugs: Pacific Northwest Insect Management Handbook https://pnwhandbooks.org/node/8078

Hand pick them off.

Also, then, even though this is a raised bed,  I would search the soil for a tunnel or disturbed soil and roots under the plant that might have been caused by a critter.  And make sure your soil is evenly moist.

There is no evidence that this is a diseased or nutrient deficient plant.

That being said.  I am copying an article with photos of  a squash disease  that causes sudden collapse. 

Phytophthora crown and root rot Phytophthora capsici

Rotting crown of yellow summer squash infected with Phytophthora

Dark discoloration of stem

Phytophthora symptoms on pattapan squash

Squash plant showing symptoms of wilt caused by Phytophthora root and crown rot

Wilted foliage of squash caused by Phytophthora infection

Symptoms

Sudden and permanent wilting of plant; leaves do not change color; plant death within a few days; roots and stem close to soil line discolored light to dark brown; plant easily removed from soil

Cause

Oomycete

Comments

Fungus can be spread through air; disease emergence favors high temperatures and water saturated soil

Management

Efficient management of water to avoid saturated soil; avoid long periods of irrigation