It is possible to monitor UNIX system load average and if it crossed certain limit an email can be send to admin user or even text via pager/sms.

1) Download/view chksysload.bash script

2) Open script using vi:
# vi chksysload.bash

3) Customize it according to your needs:
# Setup up limit below
NOTIFY=”6.0″
# Setup admin user email-id
EMAIL=”me@mycorp.net”
# Subject for email
SUBJECT=”Alert $(hostname) load average”

4) Save and close the file.

5) Install script as cronjob