Huge Spike Server Load Of 192 O.O

Just few mins ago, my site went down so I went to check up through putty, and when i put Top this is what i got:

top - 09:49:35 up 5 days, 14:41, 2 users, load average: 192.59, 109.31, 62.29
Tasks: 299 total, 3 running, 296 sleeping, 0 stopped, 0 zombie
Cpu(s): 4.0% us, 5.3% sy, 0.0% ni, 0.0% id, 88.7% wa, 0.3% hi, 1.7% si
Mem: 1009272k total, 1001268k used, 8004k free, 124k buffers
Swap: 3919840k total, 1518816k used, 2401024k free, 14676k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
14263 apache 17 0 201m 9m 3788 D 1.0 1.0 0:04.74 httpd
16772 apache 17 0 152m 13m 5340 R 1.0 1.4 0:00.82 httpd
16881 apache 16 0 155m 14m 5368 D 1.0 1.4 0:00.52 httpd
16767 apache 16 0 154m 14m 5352 D 0.7 1.4 0:00.48 httpd
16864 apache 16 0 155m 15m 5364 D 0.7 1.6 0:00.80 httpd
16874 apache 17 0 155m 14m 5416 D 0.7 1.4 0:00.60 httpd
8900 apache 17 0 200m 12m 3844 D 0.3 1.3 0:10.60 httpd
13680 apache 17 0 202m 10m 3944 D 0.3 1.0 0:06.05 httpd
14687 apache 17 0 202m 11m 4060 D 0.3 1.2 0:06.12 httpd
14838 apache 16 0 206m 16m 5624 D 0.3 1.6 0:08.19 httpd
15858 apache 17 0 152m 13m 5452 D 0.3 1.4 0:01.39 httpd
16593 apache 17 0 150m 9180 3664 D 0.3 0.9 0:00.49 httpd
16668 apache 17 0 200m 7304 3496 D 0.3 0.7 0:00.72 httpd
16703 apache 17 0 149m 7208 3192 D 0.3 0.7 0:00.61 httpd
16750 apache 17 0 151m 14m 5268 D 0.3 1.5 0:00.81 httpd
16855 apache 17 0 200m 6616 3480 D 0.3 0.7 0:00.68 httpd
16863 apache 17 0 156m 13m 5500 D 0.3 1.3 0:00.61 httpd

But after few mins, the server load went down to 5 What could've caused the huge server overload problem?

Server spec:
64 3500+
1Gb of Ram